Glossary

Plain English glossary of digital words

155 words that turn up in settings screens, scam warnings, product pages and news stories, each in one or two sentences you can actually use.

155 terms

3

3-2-1 backup rulethe rule applied to a real home: A simple target for backups: three copies of anything you care about, on two different kinds of storage, with one of them kept somewhere else. The offsite copy is what survives a fire, a theft or a drive that fails while plugged in.

A

Access pointcovering a room the router cannot reach: A device that creates a wifi network for phones and laptops to join, usually wired back to the router. Home routers include one, and adding a separate access point on an ethernet cable is the tidiest way to cover a far room.
Account takeoversteps once an account is exposed: When someone else gains control of an account of yours, changes the recovery email or phone number, and locks you out. Getting it back is far easier within the first hours, which is why sign-in alerts deserve more attention than they get.
Adwarefixing a browser full of pop ups: Software that injects advertisements, changes your homepage or sends searches through pages that pay its author. Usually bundled with a free download or a browser extension, it is more nuisance than theft, but it shows something got permissions it should not have.
AI agentwhen a chatbot starts acting: A system that uses a model to decide on and carry out steps toward a goal, such as browsing, filling in forms or sending messages, rather than only producing text. The risk shifts from a wrong answer to a wrong action.
AI biaswhere bias creeps into models: Systematic skew in what a system produces that disadvantages particular groups, inherited from patterns in the training data or from how the thing was tuned and tested. It shows up most sharply in decisions about people, such as screening job applicants.
AI detectorwhy a detector score proves little: A tool that guesses whether text or an image was machine generated and returns a score or probability. The guesses fail in both directions, flagging careful human writing and missing lightly edited machine output, so a result is not evidence on its own.
Alignment: The work of making a system's behavior match what its developers and users actually intend, including declining harmful requests and following instructions honestly. Most of it happens after the main training run, through feedback on the answers produced.
Antiviruscleaning up a machine that is infected: Software that scans files and program behavior for known malicious patterns, then blocks or quarantines what it finds. Windows and macOS now include capable protection by default, so a separate product mainly adds extra features rather than basic safety.
Application programming interface (API): A way for one program to talk to another over the internet with no person in the middle. AI companies sell access this way and charge by the amount of text sent and returned, so most tools built on a model run through one.
Artificial general intelligence (AGI)why people disagree about AGI: A hypothetical system able to learn and handle any intellectual task a person can, instead of being good at particular ones. There is no agreed test for it, which is why claims that it is close or still distant are hard to settle.
Artificial intelligence (AI)a plain English definition of AI: Software that performs tasks we associate with human thinking, such as writing, translating, recognizing faces or driving a car, by finding patterns in large amounts of data rather than following rules a person wrote out step by step.
Authenticator appsetting one up with working backups: An app on your phone or computer that generates sign-in codes on the device itself, with no network connection needed. Safer than text messages, but you must save the backup option first, because losing the phone otherwise locks you out.
Authorized push payment fraudthe first hour after you pay a scammer: A scam where you send the money yourself, from your own banking app, after being convinced the payment is genuine. Because you approved it, the protections that cover card payments do not apply, and getting it back depends on how fast the banks move.
Auto renewalfinding the subscriptions you forgot: A subscription term that charges you again at the end of each period unless you cancel first. Introductory prices usually renew at the full rate, and the charge often lands on a card you no longer watch, which is how forgotten subscriptions survive.

B

Backhaulhow mesh units talk to each other: The link a mesh unit or access point uses to carry traffic back to the main router, either over a spare wifi radio or an ethernet cable. Wired backhaul is what turns a mediocre mesh setup into a reliable one.
Backup versus cloud syncbackups that work when you need them: A backup is a separate copy kept so you can recover files after loss, theft or damage. Cloud sync instead mirrors one live set of files across devices, so a deletion or an encryption by ransomware spreads everywhere unless version history saves you.
Bandwidthhow much speed a home really needs: The maximum amount of data your connection can carry per second, usually quoted in megabits. It sets a ceiling rather than a guarantee, and once the ceiling is higher than anything your household actually does, paying for more changes nothing.
Benchmarkchoosing an assistant without leaderboards: A standard set of test questions used to compare models and produce the scores in launch announcements. They are easy to over read, since test material can leak into training data and a high score rarely predicts performance on your own work.
Biometricswhen face unlock is the safer option: Using a physical trait such as a fingerprint, face or voice to unlock a device or approve a payment. Convenient and hard to guess, but you cannot change a fingerprint once it is copied, and the legal protections differ from those around a PIN.
Botnet: A collection of computers, routers or cameras infected and controlled remotely, then rented out to send spam, guess passwords or knock websites offline. Owners rarely notice, because the device keeps working and only gives up spare capacity.
Browser extensionwhat an extension is allowed to see: A small add on that changes how your browser behaves, for blocking ads, saving passwords or clipping pages. Most need permission to read and alter every page you open, so an extension that changes owners can quietly become something else.
Browser fingerprintingidentification without any stored file: Identifying a visitor from the combination of details a browser gives away, such as screen size, installed fonts, time zone and graphics behavior. It stores nothing on your device, so clearing cookies or opening a private window does not shake it off.
Brute force attackwhy length beats clever symbols: Guessing a password or PIN by trying combinations at high speed until one works. Length is the main defense, since each extra character multiplies the work, and most services now slow down or lock an account after repeated failures.

C

Cache: A local copy of files a program has already fetched, kept so the next visit loads without downloading everything again. It is why a page can show an old version after a site changes, and why clearing it fixes some display problems.
Caller ID spoofingwhy the number on screen means little: Faking the number that shows on your phone so a call or text appears to come from your bank, the police or a local area code. The displayed number proves nothing, so a call matching the number on your card can still be a stranger.
Chain of thoughtmodels that work through steps: Working through intermediate steps before stating an answer, either because you asked for it or because the system does it by default. It improves accuracy on multi step problems, though the written steps are a reconstruction rather than a record of the real process.
Chargebackgetting money back after a bad payment: A card payment reversed by your bank after you dispute it, used when goods never arrive or a charge is not what you agreed. It runs through the card network rather than the seller, so it is a different route from asking the shop for a refund.
Coalition for Content Provenance and Authenticity (C2PA)how provenance labels are built: The industry standard that defines how origin and editing history are written into a file and cryptographically signed, so later tampering shows up. Content Credentials is the consumer facing label built on it, and camera makers and editing tools are adding support.
Content Credentialsthe provenance label on a photo: A tamper evident label attached to a photo, video or file that records where it came from and which tools edited it. Its absence proves nothing, because many platforms strip the information when a file is uploaded or saved again.
Content delivery network (CDN): A network of servers spread around the world that hold copies of a site's files and serve each visitor from a nearby one. It makes pages load faster, and it is why trouble at one large provider can take down many unrelated sites at once.
Context windowwhy long chats lose the beginning: The maximum amount of text a model can hold in view at once, counted in tokens and covering the conversation, your files and its own replies. Go beyond it and the earliest material is dropped or summarized, so details go missing.
Cookiewhat reject all really does: A small file a site stores in your browser so it can recognize you on the next page or the next visit. Some keep you signed in or hold your basket, while others exist only to build a record of what you look at.
Credential stuffingthe real cost of reusing one password: Taking username and password pairs leaked from one site and trying them automatically across hundreds of others. It costs the attacker almost nothing and succeeds wherever someone reused a login, which is how an old leak unlocks newer accounts.
Credit freezewhat to do when your details are misused: A lock you place on your credit file so lenders cannot run a new check, which stops most applications made in your name. It is free, you lift it temporarily when you need credit yourself, and it leaves existing accounts untouched.

D

Dark webcheck whether your login already leaked: Sites reachable only through special software that hides both the visitor and the server. Trade in stolen logins happens there, which is what a monitoring service means when it warns that your email address has been found.
Data breachwhat a leak actually means for you: An incident where information a company held about its customers is copied or exposed, often email addresses, passwords and order histories. What leaked matters more than the headline number, because a password can be reused elsewhere while a postal code cannot.
Data subject access request (DSAR)what you can ask a company to do: A formal request asking an organization for a copy of the personal data it holds about you, what it uses that data for and who it shares it with. Data protection law in the UK and EU requires an answer within a set time limit.
Deep learningthe basics of learning from data: Machine learning that stacks many layers of simple calculations so a system can pick up patterns that shallower methods miss. The depth is what made modern image recognition and chatbots possible, and it is why they need so much data and computing power.
Deepfakewhat still gives AI video away: A video, image or audio clip generated or altered so a real person appears to say or do something they never did. Convincing ones are cheap to make now, so trust should rest on the channel and context, not on how real it looks.
Diffusion modelturning noise into a picture: An image generator trained to start from random visual noise and remove it step by step until a picture matching the description emerges. Working backward from noise is why the same request produces a different image every time.
Distillation: Training a small model to imitate the outputs of a large one, so it keeps much of the behavior at a fraction of the running cost. Most compact assistants that run on phones and laptops are produced this way.
DNS resolverwho answers your lookups, and sees them: The server that answers your device's name lookups, usually run by your internet provider unless you change it in the router or the phone settings. Because every site you visit starts with a lookup, whoever runs it sees your browsing in outline.
Domain namewhich part of an address actually matters: The registered name a website is reached by, such as example.com, made of a chosen label and the ending after the final dot. Scam links often keep a familiar word somewhere in the address while the registered name is something else entirely.
Domain Name System (DNS)the phone book behind every address: The system that turns a name you type, such as example.com, into the numeric address a computer can connect to. When it fails or answers slowly, sites appear to be down even though the connection itself is working normally.
Driver: A small piece of software that lets an operating system talk to a particular piece of hardware, such as a printer or a graphics chip. Fake driver update tools are a common way unwanted software arrives, so take them from the maker's own site.

E

Embedding: A list of numbers representing the meaning of a piece of text or an image, arranged so that similar items sit close together. It powers search that matches meaning rather than exact words, and underpins most document question answering.
Encrypted DNSkeeping name lookups private: Name lookups sent over an encrypted connection, so the network you are on cannot read or alter them. Browsers and phones increasingly switch it on by default, which hides the list of sites you visit from anyone watching the local network.
Encryption: Scrambling data with a key so only someone holding the matching key can read it. It protects information crossing a network and files on a lost laptop, but it does nothing once an attacker can simply sign in as you.
End of supportknowing when a phone is genuinely done: The point where a maker stops issuing updates for a device or a program, so newly discovered security holes stay open. Everything keeps working, which is what makes it easy to miss, and it is a better reason to replace something than a slow feeling.
End-to-end encryption: An arrangement where a message is locked on the sender's device and unlocked only on the recipient's, so the company carrying it cannot read the contents. Cloud backups, screenshots and anyone glancing at the recipient's screen sit outside that protection.
Entropytest how strong a password really is: A measure of how unpredictable a password is, based on how it was generated rather than how complicated it looks. A phrase you invented yourself has far less than a random string of the same length, because human choices follow patterns.
Ethernetwhen a cable beats more wifi: A wired network connection using a cable with a clip on plug, running between your router and a device. It sidesteps the interference and distance problems of wifi entirely, so it stays the most reliable option for desks, consoles and televisions.
Exploit: The specific code or sequence of steps that turns a software weakness into real access, such as running a command or reading another account's files. Security reports separate a theoretical flaw from one already being used, and that gap decides how urgent a fix is.

F

Factory resetwiping a device before it moves on: Returning a device to the state it left the factory in, removing your accounts, apps and files. Sign out of the manufacturer's account before you reset a phone for sale, otherwise it can stay locked to you and useless to the buyer.
Few shot promptinggiving the model worked examples: Including two or three worked examples of the input and the output you want, so the model copies the pattern instead of guessing. It is usually the fastest fix when an answer is right in substance but wrong in shape.
Fiber versus cable broadband: Fiber carries your connection as light along glass strands, usually giving upload speeds close to the download figure. Cable broadband uses the coaxial television network for the last stretch, which downloads quickly but is typically much slower going out.
Fine tuningwhen fine tuning is the right tool: Taking an already trained model and training it further on a smaller, focused set of examples so it adopts a particular style, format or vocabulary. It changes how a model behaves, but it is a poor way to give it fresh facts.
Firewall: A filter built into your router or operating system that decides which network connections may pass in and out. It turns away uninvited traffic from the internet, but it has no say over a harmful file you chose to download and open.
Firmwarewhich updates deserve attention now: The software built into a piece of hardware, such as a router, printer or television, that makes the device work at all. It updates far less often than apps, and it is usually where fixes for holes in the device itself arrive.

G

Graphics processing unit (GPU): A chip designed to run very many simple calculations at once, originally for rendering graphics and now the standard hardware for training and running AI. Their scarcity and electricity use shape what AI costs and where data centers get built.
Guardrails: Extra checks wrapped around a model that block certain inputs or outputs, such as filters for personal data, abuse or off topic requests. They sit outside the model, so they can be changed without retraining and can also be worked around.

H

Hallucinationwhy AI makes things up: A confident, fluent answer that is simply untrue, such as an invented citation, quotation or product feature. It happens because the system predicts plausible text rather than looking facts up, so nothing inside marks the difference between recall and invention.
Hashing: Turning a password into a fixed-length string that cannot practically be turned back, so a site can check your login without keeping the original text. When a well-run service is breached, attackers get these scrambled values rather than usable passwords.
HTTPSwhat the padlock really proves: The encrypted version of the protocol browsers use to fetch pages, shown by an address beginning https. It stops others on the network reading or changing what passes between you and the site, but says nothing about whether the site is honest.

I

Identity theftspotting it early and acting fast: Someone using your personal details to open accounts, claim benefits or borrow money in your name. The early signs are usually small: a letter about an account you never opened, or a credit check you did not request.
Inferencehow a model produces each word: Running a finished model to get an answer, as opposed to training it in the first place. Every message you send is one, and the cost scales with how much text goes in and comes out, which is what usage limits ration.
IP addresshow names turn into addresses: The numeric label identifying a device on a network, so replies know where to come back to. Your home has one public address from your provider, while each device on your wifi holds its own private address behind the router.

J

Jailbreak: A message crafted to talk a model out of its own safety rules, often through roleplay, hypothetical framing or a flood of confusing instructions. Providers patch the ones they find, and new variants keep appearing, so no filter should be treated as final.
Jitterthe readings a speed test hides: Variation in latency from one moment to the next, so packets arrive unevenly instead of in a steady stream. It is the usual reason a video call breaks up or a voice sounds robotic even when the measured speed looks fine.

K

Keylogger: A program or small hardware device that records every key you press, capturing passwords and card numbers as you type them. Because it reads the text before anything is encrypted, a long password gives no protection while one is running.
Knowledge cutoffwhy your AI misses last week: The point after which a model saw no training data, so it knows nothing about later events unless it searches the web or you paste the information in. Many will answer about recent events anyway, using stale facts.

L

Latency (ping)what the second number on a test means: The delay before data starts moving, measured in milliseconds and shown on a speed test as ping. Low latency is what makes video calls and games feel responsive, and a very fast connection with high latency still feels sluggish.
Local modelrunning a model on your device: A version of an AI system that runs on your own computer or phone rather than a company's servers, so prompts never leave the device. It works offline and costs nothing per question, at the price of slower and weaker answers than the largest hosted services.

M

Machine learninghow software learns from examples: A way of building software by showing it many examples and letting it work out the patterns itself, instead of a programmer specifying every rule. Almost everything sold as AI today, from spam filters to chatbots, is built this way.
Malwarewhich infection does what, in plain terms: Any software written to damage a device, steal information or take control of it, covering viruses, ransomware, spyware and more. Most of it arrives through a file you opened, an app from outside the official store, or an extension you approved.
Master passwordhow one app can hold every login: The single password that unlocks everything else inside a password manager. In most designs the company cannot reset it, so it needs to be long, memorable and written down somewhere physically safe as a last resort.
Megabit versus megabytemaking sense of speed test numbers: Internet speeds are sold in megabits per second (Mb or Mbps), while file sizes are measured in megabytes (MB). Eight bits make a byte, so divide the advertised speed by eight to see how fast a download will really feel.
Mesh networkwhich fix suits your dead zone: A set of matched wifi units that cover a home under one network name, handing your device from one unit to the next as you move. Coverage comes from placing several units rather than from one router trying to shout further.
Model sizedoes bigger really mean better: A shorthand for how many parameters a trained system holds, used to rank one release against another. Larger generally handles harder tasks but costs more and answers slower, and a smaller recent release often beats a bigger older one.
Modem versus routerwhere the box should sit in your home: The modem is the box that turns your provider's incoming line into home network traffic; the router shares that connection between your devices and runs the wifi. Many providers combine both in one unit, which is why the words get used interchangeably.
Multi-factor authentication (MFA)extra sign-in steps in plain English: The general name for requiring two or more independent proofs of identity: something you know, something you have and something you are. Workplaces use the phrase for anything sensitive, and it covers setups with more than two steps.
Multimodal: A system that handles more than text, taking in or producing images, audio or video in the same conversation. It is why you can photograph a form and ask questions about it instead of typing out the contents.

N

Narrow AIwhat counts as AI today: A system that does one kind of task well, such as transcribing speech, recommending films or flagging fraud, and cannot carry that skill across to anything else. Everything in use today is this kind, however general a chatbot feels in conversation.
Neural networkwhat sits inside a trained model: A mathematical structure loosely inspired by brain cells, built from layers of numbers that pass signals to each other. Training adjusts those numbers until the output is useful. Nothing inside stores facts as sentences, which is why a model cannot simply look up what it knows.

O

One-time codewhere those sign-in codes come from: A short number, valid for a few minutes and a single use, sent by text or generated in an app to confirm a sign-in or a payment. No genuine company ever needs you to read one back to a caller.
Open source softwareopen source for people who are not developers: Software whose source code anyone can read, change and share, often built by a community rather than a single company. Public code does not by itself make a program safe or well maintained, so the size and activity of the project still matter.
Open weightswhat open really means for models: A model whose trained numbers are published for anyone to download, run and adapt on their own hardware. This is not the same as open source, since the training data and code usually stay private and the license may restrict commercial use.
Operating system: The software that runs a device and everything on it, handling the screen, the files and the apps you install. Windows, macOS, Android, iOS and Linux are the common ones, and an app has to be written for the family you use.

P

Packet lossdiagnosing a slow connection in order: Data crosses a network in small chunks called packets, and some never arrive, so they have to be sent again. Even a small share going missing makes calls stutter and pages stall while the speed number on a test still looks healthy.
Parameterwhether more parameters means better answers: One of the numbers inside a model that gets adjusted during training and then decides how an input turns into an output. Models are often ranked by how many they contain, which indicates scale rather than answer quality.
Passkeysigning in without any password: A sign-in method that keeps a private key on your phone, laptop or security key and releases it only after your face, fingerprint or device PIN. Nothing gets typed, so there is no password to steal, reuse or hand to a fake site.
Passphrasewhy four random words win: A password built from several unrelated words, easy for a person to remember and long enough to resist guessing. Four random words picked by a machine beat a short word with letters swapped for symbols, which people reuse and computers crack quickly.
Password managerthe case for keeping logins in one app: An app that creates, stores and fills a different long password for every account, all locked behind one key you remember. Its biggest benefit is ending reuse, and it refuses to fill a login on a lookalike domain that fools people.
Patchwhich updates to install right away: A small update that closes a specific security hole rather than adding features. Installing it quickly matters because the details of the flaw usually become public alongside the fix, and the people who write attacks read those notes too.
Phishinghow fake messages get past careful people: A message that imitates a company or person you trust and asks you to sign in, pay or confirm details, so whoever sent it captures what you type. The giveaway is usually the link destination and the pressure to act immediately, not bad spelling.
Powerline adaptercabled alternatives to more wifi: A pair of plugs that send network traffic through your home's electrical wiring, giving a wired link where running a cable is impractical. Speed depends heavily on the state of the circuit, and adapters on different circuits often disappoint.
Promptwriting a request that works: Everything you send a model in one turn: the question, any instruction about tone or format, and any text or image you paste in. Small changes in wording often change the answer more than switching to a different model does.
Prompt injection: An attack that hides instructions inside content a model reads, such as a web page, email or attachment, hoping the system obeys them instead of you. It matters most for agents, which may act on the smuggled instruction rather than just repeat it.

Q

Quantization: Storing a model's numbers at lower precision so it takes less memory and runs on ordinary hardware. The trade is a small loss of accuracy, and it is what lets a large model fit on a laptop or phone at all.

R

Random access memory (RAM)how much memory is actually enough: The fast working memory a computer uses for whatever is open right now, cleared every time it shuts down. Running short is what makes a machine crawl with many tabs and apps open, and it is a separate thing from storage space.
Ransomwarehow it gets in and what helps: Software that encrypts your files and demands payment for the key, often after sitting quietly on a network for days first. Paying does not reliably bring the files back, which is why a backup kept disconnected is the real defense.
Rate limitwhat a paid plan buys: A cap on how many requests, or how much text, you can send in a given period. Hitting one produces a try again later message rather than a wrong answer, and paid plans usually raise the ceiling rather than remove it.
Reasoning modelwhen a model thinks first: A model trained to spend extra computation working through a problem internally before replying. It tends to do better on math, code and logic puzzles, and in exchange it is slower and more expensive for each answer.
Recovery codesgetting back in when your phone is gone: One-time backup codes a service gives you when you switch on a second sign-in step, for the day your phone is lost, stolen or broken. Store them outside the account they protect, because that is exactly when you cannot log in to look them up.
Reinforcement learning from human feedback (RLHF)the stages of model training: A training stage where people rate or rank a model's answers and the system is adjusted to produce more of what they preferred. It turns a raw text predictor into something that follows instructions, and it also bakes in the raters' tastes.
Retrieval augmented generation (RAG)choosing between retrieval and retraining: A setup where the system first searches your documents, then hands the relevant passages to the model along with your question. The answer comes from text just supplied rather than from memory, which makes sources checkable and updates immediate.

S

Safe account scamhow bank impersonation calls unfold: A caller posing as your bank or the police says your money is at risk and tells you to move it to a new account, which they control. No real bank asks you to transfer money for safekeeping.
Salting: Adding a unique random value to each password before it is scrambled for storage, so two people who chose the same password end up with different stored results. Without it, one precomputed table cracks thousands of accounts at once.
Secure enclavewhat your phone stores about your face: A separate chip or walled-off part of the processor that holds fingerprint and face data and cryptographic keys, kept away from the main operating system and apps. Your face is never uploaded; only a yes or no answer leaves the chip.
SIM swap: When a fraudster persuades or bribes a mobile carrier to move your phone number onto their SIM card, capturing the calls and codes meant for you. The first sign is usually a phone that suddenly loses service for no reason.
Smishingthe warning signs in a scam text: Fraud that arrives as a text message, usually a missed delivery, a bank alert or a tax refund, carrying a link to a page that harvests your details. Phone screens hide most of a web address, which is why these succeed more often than email.
Social engineering: Manipulating a person instead of breaking software: building trust, inventing urgency or posing as authority until someone hands over access. Most successful attacks start here, because persuading one tired employee is far cheaper than defeating encryption.
Solid state drive (SSD)what to look for on a spec sheet: Storage built from flash memory chips with no moving parts, used in place of a spinning hard disk. It is the single biggest reason a modern machine starts and opens files quickly, and it keeps its contents when the power is off.
Spear phishingwhy a convincing message still fools you: A targeted fake message aimed at one person or a small team, using real names, projects and suppliers gathered beforehand so it fits the recipient's day. It works on cautious people because nothing looks generic and the request sounds expected.
Spyware: Software installed without meaningful consent that watches what you do, including messages, location, browsing and keystrokes, and sends it elsewhere. It usually hides its icon, so the clues are battery drain, heat and unexplained data use.
SSIDwhy some homes show two network names: The name a wifi network broadcasts, which is what you pick from the list on your phone. Routers ship with a factory name printed on a label, and some homes split the bands into two names so you can choose which one to join.
Stalkerware: Monitoring apps sold openly for tracking a partner, child or employee, put on someone's phone by a person with physical access to it. Removing it can alert whoever installed it, so safety planning should come before cleanup.
Storage versus memorythe difference that changes what you buy: Storage is the space that keeps your files when the power is off, measured in gigabytes on a drive; memory is the temporary space holding whatever is open now. A spec sheet lists both, and more of one does not help when the other is short.
Subdomainhow the parts of an address fit together: A section placed in front of a domain name and separated by a dot, used to point at a particular service such as mail or a regional site. Anyone who owns a domain can create any subdomain they like, so the words there prove nothing.
Sycophancywhy an AI agrees with you: The tendency to agree with whatever you assert and to soften corrections, because training rewarded answers that people liked. It matters when you ask an assistant to check your work, since pushing back once can flip a correct answer into a wrong one.
Synthetic datawhere training data comes from: Training material generated by another model rather than collected from people. It fills gaps where real examples are scarce, expensive or private, though errors can compound when a system learns mostly from the output of other systems.
System promptthe hidden instructions behind a chatbot: A standing instruction the product sends the model before your message, setting its persona, its rules and what it must refuse. You normally never see it, and it explains why the same underlying model behaves differently in two apps.

T

Temperaturethe dials that change AI answers: A setting that controls how much randomness goes into picking each next word. Low values give repetitive, predictable output that suits data extraction and code, while higher values give more varied phrasing and more mistakes.
Text to imagewriting prompts for better pictures: A tool that turns a written description into a picture. Results depend heavily on naming the subject, style, lighting and framing, because whatever you leave out is filled in with whatever was most common in the pictures it learned from.
Third party cookiehow you get followed between sites: A cookie set by a company other than the site you are reading, usually through an advertisement or an embedded widget. Because the same company appears on many sites, it can join your separate visits into a single profile.
Time-based one-time password (TOTP)how app-generated codes are produced: The rotating code an authenticator app shows, calculated from a secret shared once with the site and the current clock rather than sent over the network. Because nothing is transmitted, it survives a hijacked phone number.
TLS certificatethe identity check behind the padlock: A file a website presents to prove it controls the name you typed and to set up the encryption. Browsers check it automatically, so a warning means the name does not match or the file has expired, which is worth taking seriously.
Tokenwhy tokens decide your bill: The unit a language model reads and writes, usually a whole word, part of a word, or a punctuation mark. Usage limits and bills are counted this way, so a long document costs more than its page count suggests.
Tokenizationhow text is split for a model: The step that chops your text into the small pieces a model can process before anything else happens. It explains odd behavior such as miscounting the letters in a word, because the system never sees individual characters, only chunks.
Tool usehow assistants take actions: A model's ability to call outside functions, such as a search engine, a calculator or your calendar, and fold the results into its reply. It is how an assistant gets current information and does things text prediction alone cannot.
Top level domain (TLD)what the ending of an address tells you: The ending of a domain name, such as .com, .org or a country code like .uk. A few endings have rules about who may register them, but most are open to anyone, so the ending alone says little about whether a site is trustworthy.
Top-poutput settings beyond temperature: A setting that limits each word choice to the smallest group of likely candidates reaching a set share of the probability, discarding the unlikely tail. Like temperature it trades predictability against variety, and changing both at once makes results hard to interpret.
Tracking pixelthe invisible image in an email: A tiny invisible image loaded from another server, used to record that you opened a page or an email. It reports the time, your rough location and the device you used, which is how a sender knows their message was read.
Trainingfrom raw text to chatbot: The process of feeding a model huge amounts of text, images or other data and repeatedly adjusting its internal numbers until its predictions improve. It happens once, ahead of time, and costs far more than answering any single question later.
Training data opt outstopping your chats training a model: A setting or form that tells a provider not to use your conversations and uploads to improve its models. It is often switched off by default on free consumer plans, and it rarely reaches data that has already been used.
Trojana plain guide to malicious software: A program that presents itself as something useful, a game, a cracked app or a document viewer, then quietly installs something harmful once you run it. It depends entirely on your permission rather than on any flaw in the system.
Two-factor authentication (2FA)what the second step really protects: A second check after your password, usually a code, an app prompt or a physical key, so a stolen password alone is not enough to get in. Codes sent by text are the weakest version and still far better than nothing.

U

Upload speedmatching a plan to what you actually do: How fast your connection sends data out, as opposed to pulling it in. It matters for video calls, cloud backups and sending large files, and on many cable plans it is a small fraction of the download figure in the advertisement.
URLreading a web address properly: The full address of a page, made up of the protocol, the site name and the path to the specific document. Knowing which part of it is the real site name is what lets you spot a link that only looks familiar.

V

Vector database: A store built to hold embeddings and find the closest matches to a query quickly. It is the piece that lets an assistant pull the three most relevant paragraphs out of thousands of company documents before it answers.
Virtual private network (VPN)the three things a VPN cannot do: A service that sends your traffic through an encrypted tunnel to a server elsewhere, so the local network sees only the tunnel and websites see the server's location. It hides your traffic from the network you are on, not from the VPN company.
Virushow the different infections differ: Malicious code that attaches itself to a file or program and spreads when that file is run or shared. The word is now used loosely for every infection, though most current threats travel through downloads and fake update prompts instead.
Vishinghow pressure tactics work on a call: A phone call that pretends to come from your bank, a government office or a support desk, talking you into codes, passwords or payments. A live voice creates urgency that text cannot, and the caller often insists you stay on the line.
Voice cloninghow a cloned voice is used: Software that copies how someone sounds from a short recording, then speaks new words in that voice. A few seconds taken from a video or voicemail is enough, which is why a familiar voice on a call is no longer proof of identity.
Vulnerability: A weakness in software, hardware or a process that could let someone do something they should not, such as reading another user's data. Most are found and quietly fixed; the risk becomes real only once somebody works out how to use it.

W

Watermarkspotting a generated image: A marker placed in generated text, images or audio to identify where they came from, sometimes visible and often hidden in the data itself. Hidden ones survive light editing but not determined removal, so they help platforms more than individual viewers.
WebAuthnwhat happens behind a passkey prompt: The browser standard that lets a website ask your device to prove who you are using a stored key instead of a password. You rarely see the name itself; it is the machinery behind passkey and security key prompts.
Weightswhat a model actually stores: The stored parameter values that make up a finished model, the entire result of a training run. Copying them copies the model, which is why publishing them is a far bigger decision for a company than releasing an app.
Wifi 6what the band and generation labels mean: A generation of wifi designed to handle many devices at once rather than to make a single download faster. The gain shows up in a busy household, and only when the router and the device you are using both support it.
Wifi bandthe bands compared in plain English: The stretch of radio spectrum a wifi network uses, commonly 2.4, 5 or 6 GHz. Lower bands travel further through walls but carry less data, which is the trade you are making whenever a device settles on the slower one.
Wifi channelfixing the evening slowdown: A narrower slice within a wifi band, rather like a lane on the same road. Networks sharing a lane have to take turns, which is why moving to a quieter channel can fix a slowdown that appears every evening.
Wifi extenderwhen an extender is the wrong tool: A small plug in box that picks up your existing wifi signal and rebroadcasts it further into the house. It talks to the router and to your devices over the same airtime, so the extended side is usually slower than a room served directly.

Z

Zero-day: A flaw that the software maker has not fixed yet, and sometimes has not heard about, while attackers are already using it. It is the reason a security update occasionally appears on its own, outside the normal release schedule.
Zero-knowledge encryptionwhy the provider cannot read your data: A design where your data is locked on your device before it reaches the provider, so their servers hold only unreadable content and never your key. Password managers advertise this, and it also means nobody can recover anything if you forget the key.