Beginner

AI Words Explained: A Plain-English Glossary

By Abdelmounaim Dib · Updated November 2026 · 10 min read

AI comes with a lot of new words, and most explanations make them sound harder than they are. Here are the 30 terms you are most likely to hear, explained in one or two plain sentences, with an everyday example where it helps. Bookmark this page and come back whenever a word confuses you.

The basics

AI (artificial intelligence)

Computer programs that can do tasks we usually connect with human thinking, like understanding language, recognizing pictures or making suggestions. Your phone's face unlock and your email's spam filter are both AI.

Generative AI

AI that creates something new: text, images, music, voices or video. ChatGPT writing an email or an app turning your words into a picture are examples. This is the kind of AI most people mean today.

Chatbot

An app you talk to in normal language, by typing or speaking, and it answers. ChatGPT, Gemini, Copilot and Claude are chatbots. See our comparison of the four free ones.

Model

The "brain" behind a chatbot. One app can offer several models: smaller ones that are fast and free, and bigger ones that are smarter but often paid. When people say "the new model", they mean an upgraded brain inside the same app.

LLM (large language model)

The type of model behind chatbots. It learned from a huge amount of text and works by predicting which words should come next. That is why it writes so fluently, and also why it can sound sure while being wrong.

Prompt

Whatever you type or say to the AI. "Write a birthday message for my sister" is a prompt. Better prompts get better answers: see our 7 prompt tricks and 25 ready-made prompts.

Response (or output)

What the AI gives back to you: the text, image or spoken answer.

How AI works (without the math)

Training data

The text, pictures and other material a model learned from before it was released. A model is only as good as what it learned from.

Knowledge cutoff

The date when a model's training data ends. It does not know about events after that date unless it can search the web. That is why AI sometimes gives outdated prices or news.

Web search (in a chatbot)

When the chatbot looks things up on the internet before answering, often with links to its sources. Answers with sources are easier to check.

Token

A small piece of text, usually part of a word, that the AI reads and writes in. You rarely need to think about it, except that limits and prices for AI tools are sometimes counted in tokens.

Context window

How much the AI can "keep in mind" at once in a conversation, like a short-term memory. In a very long chat, it may forget what you said at the beginning. Starting a new chat often fixes that.

Reasoning model (or "thinking" mode)

A model that takes extra time to work through a problem step by step before answering. It is slower but better for math, planning and tricky questions.

Multimodal

An AI that understands more than text: photos, voice, files or video. Snapping a picture of a plant and asking "What is this?" uses a multimodal AI.

Features you will see in apps

Voice mode

Talking to the AI out loud and hearing it answer, like a phone call. Here is how to use AI by voice.

Memory

A feature that lets the chatbot remember details about you between conversations, such as your name or that you are vegetarian. Handy, but you can view, delete or turn it off in the settings.

Temporary chat

A private mode where the conversation is not saved to your history or memory. Good for personal questions or when you share a device.

Deep research

A mode where the AI spends several minutes searching many websites and writes a longer report with sources. Free plans usually allow only a few per week or month.

AI agent

AI that can take actions for you, not just answer. For example, filling in a form, comparing products on several websites or organizing files. Agents are powerful but still make mistakes, so check before letting them buy or send anything.

AI Overviews

The AI-written summary that Google shows at the top of some search results. Useful for a quick answer, but it can be wrong, so click the sources for anything important.

Image generator

A tool that creates a picture from your description, such as "a cozy cabin in the snow, watercolor style".

Words about risks and safety

Hallucination

When AI makes something up and presents it as fact: a fake quote, a study that does not exist or a wrong date. It is the biggest reason to double-check answers. Learn the warning signs in how to spot AI mistakes.

Bias

When AI gives unfair or one-sided answers because of patterns in what it learned. For example, assuming a nurse is a woman or a CEO is a man.

Deepfake

A fake video, photo or audio made with AI that shows a real person saying or doing something they never did. Be careful with shocking clips that only appear on social media.

Voice cloning

Using AI to copy someone's voice from a short recording. Scammers use it for fake "family emergency" calls. A family safe word is a simple defense, as we explain in our guide for seniors.

Data privacy (and "model training")

What happens to what you type. Some apps use your chats to improve their models unless you turn this off in the settings. Never share passwords, bank details or ID numbers with a chatbot.

Words you may hear in the news

Open-source (or open-weight) model

A model whose inner workings are published so anyone can download and run it on their own computer. ChatGPT is not open; some others are.

API

A way for apps and websites to connect to an AI model behind the scenes. When a shopping site has an AI helper, it often uses an API from one of the big AI companies.

Fine-tuning

Extra training that makes a general model better at one specific job, like answering a company's customer questions.

AGI (artificial general intelligence)

The idea of an AI that can do almost any mental task as well as a human. It is a goal some companies talk about, not something you can download today, and experts disagree on when or whether it will arrive.

Still confused by a word?

Ask the AI itself. This prompt works well:

New to all of this? Start with ChatGPT for beginners: your first 10 minutes.