The AI Glossary

Every AI word, finally clear.

The AI world is full of jargon. Here's 24 of the terms you'll actually hear — each one explained in plain English, with a real example. No degree required.

24 terms

AI (Artificial Intelligence)

Software that can do things we used to think only humans could do — like writing, answering questions, recognising images, or having a conversation.

In plain terms

When your phone suggests the next word as you type, that's a simple form of AI.

Prompt

The message or question you type to an AI tool. It's your instruction — the better your prompt, the better the response.

In plain terms

"Write a thank-you email to a client who just renewed" is a prompt.

LLM (Large Language Model)

The type of AI behind tools like ChatGPT and Claude. It was trained on enormous amounts of text and predicts what words should come next to form a useful response.

In plain terms

Think of it as an incredibly well-read assistant that has read most of the internet.

Token

The small chunks of text an AI reads and writes — roughly a word or part of a word. AI tools have limits on how many tokens they can handle at once.

In plain terms

The word "unbelievable" might be split into three tokens: un-believ-able.

Hallucination

When an AI confidently states something that's wrong or made up. It's the single most important thing to watch for — always verify important facts.

In plain terms

An AI might invent a realistic-sounding book title or statistic that doesn't actually exist.

Context Window

How much information an AI can "hold in mind" at once during a conversation — including your prompt and everything said so far. Bigger windows handle longer documents.

In plain terms

Like short-term memory: once the conversation gets very long, early details may drop off.

Training Data

All the text and information an AI learned from before you ever used it. This is why AI knows so much — and why it can carry the biases of what it read.

In plain terms

An AI's knowledge has a cut-off date — it doesn't automatically know today's news.

Fine-tuning

Taking a general AI model and giving it extra training on specific material so it gets better at a particular job or speaks in a particular style.

In plain terms

A company might fine-tune a model on its support tickets to handle customer questions in its own voice.

Generative AI

AI that creates new things — text, images, audio, video, code — rather than just analysing or sorting existing information.

In plain terms

Asking AI to write a poem or generate an image are both generative tasks.

Chatbot

An AI you interact with by chatting back and forth, like texting. Most modern AI assistants work this way.

In plain terms

ChatGPT, Claude, and Gemini are all chatbots.

Model

A specific version of an AI, often with a name and number. Newer models are usually more capable. You'll sometimes get to choose which one to use.

In plain terms

GPT-4, Claude Opus, and Gemini Pro are all models.

Parameters

The internal "settings" an AI learned during training — often billions of them. More parameters can mean a more capable (but more expensive) model. You rarely need to think about these.

In plain terms

Like the connections in a brain: more connections, more capacity to learn patterns.

Multimodal

An AI that can handle more than just text — it can also "see" images, "hear" audio, or work with multiple types of input together.

In plain terms

Uploading a photo and asking "what's in this picture?" uses a multimodal model.

Inference

The moment an AI actually generates a response to your prompt. When people say a model is "thinking," this is what's happening.

In plain terms

Every time you hit enter and wait for an answer, that's inference.

System Prompt

A behind-the-scenes instruction that shapes how an AI behaves across a whole conversation — its personality, rules, and role — before you type anything.

In plain terms

A customer-service bot might have a system prompt telling it to always be polite and never discuss competitors.

Temperature

A setting that controls how creative or predictable an AI's responses are. Low temperature is focused and consistent; high temperature is varied and surprising.

In plain terms

For a factual answer you want low temperature; for brainstorming wild ideas, higher.

RAG (Retrieval-Augmented Generation)

A technique where an AI looks up relevant information from a specific source before answering — so it can give accurate, up-to-date answers grounded in real documents.

In plain terms

An AI that searches your company handbook before answering an HR question is using RAG.

Agent

An AI that can take actions on your behalf — not just answer, but actually do multi-step tasks like booking, searching, or operating other software.

In plain terms

An AI agent might research flights, compare them, and fill in the booking form for you.

Prompt Engineering

The skill of writing prompts that get great results. It's the most valuable AI skill you can build — and the whole point of FLUENT.

In plain terms

Knowing to add context, examples, and a clear format is prompt engineering.

API

A way for software to talk to an AI directly, so developers can build AI into their own apps and websites. You don't need one to use AI tools day-to-day.

In plain terms

When an app says "powered by GPT-4," it's using OpenAI's API behind the scenes.

Open Source

AI models that anyone can download, inspect, and run themselves — as opposed to closed models you can only access through a company's product.

In plain terms

Meta's Llama models are open source; you can run them on your own computer.

Bias

When an AI's responses unfairly favour or disadvantage certain groups — usually because of patterns in its training data. Worth being aware of, especially for important decisions.

In plain terms

An AI trained mostly on one kind of writing might assume that style is "correct" for everyone.

Guardrails

The safety rules built into an AI to stop it producing harmful, dangerous, or inappropriate content.

In plain terms

Guardrails are why an AI will refuse to help with something genuinely dangerous.

Zero-shot / Few-shot

Zero-shot means asking AI to do something with no examples. Few-shot means giving it a couple of examples first to guide it — which usually improves results.

In plain terms

Showing AI two sample product descriptions before asking for a third is few-shot prompting.

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Remember

You don't need to know the jargon to use AI brilliantly. But now you do anyway.