AI glossary — plain English definitions
Every field has its jargon. AI has more than most.
Here are the terms that actually matter — the ones that come up in meetings, in news articles, and in the tools you’re starting to use. Plain English. No unnecessary complexity.
If there’s a term you don’t see here, email me.
AI (Artificial Intelligence)
Technology that can perform tasks that normally require human intelligence — understanding language, recognising patterns, making decisions. The AI tools covered in That Clicked all understand plain English instructions, which means you don't need any technical knowledge to use them.
“AI is a broad term. When most people say AI right now, they mean the kind that understands and generates language — tools like Copilot, ChatGPT, and Claude. That's what we focus on here.” — Anna
ChatGPT
An AI assistant made by OpenAI. Available at chat.openai.com and as a mobile app. One of the most widely used AI tools in the world. Good for writing, research, analysis, and general tasks. Has a free version and a paid version (ChatGPT Plus).
Claude
An AI assistant made by Anthropic. Available at claude.ai. Known for being particularly good at longer, more nuanced writing and analysis. Has a free version and a paid version (Claude Pro). That Clicked's AI practice tool is powered by Claude.
Copilot (Microsoft)
Microsoft's AI assistant, built into Microsoft 365. Sits inside Outlook, Teams, Word, Excel, and PowerPoint. Helps with email summaries, meeting notes, document drafting, and data analysis. Available depending on your company's Microsoft licence. Covered in depth in Module 1 of That Clicked.
Gemini
Google's AI assistant. Available at gemini.google.com and built into Google Workspace tools (Gmail, Docs, Sheets). Google's equivalent of Copilot for Microsoft users.
Hallucination
When an AI confidently states something that is factually wrong. All current AI tools do this sometimes. It's not a glitch — it's a known limitation of how these systems work.
“This is why you always check anything important that AI produces. Use it for drafts and first passes — not as a source of truth.” — Anna
Large Language Model (LLM)
The technical term for the type of AI that powers tools like ChatGPT, Copilot, Claude, and Gemini. Trained on vast amounts of text, which is how they understand and generate language. You don't need to understand how they work to use them well — but it's useful to know the term when you see it.
Perplexity
An AI-powered search tool. Available at perplexity.ai. Unlike ChatGPT or Claude, Perplexity searches the web in real time and shows you the sources it used. Particularly useful for research tasks where you need current, verifiable information.
Prompt
The instruction you give to an AI tool. The quality of what you get back depends heavily on the quality of your prompt. A vague prompt gets a vague answer. A specific, well-structured prompt gets something genuinely useful.
“Learning to write good prompts is the whole skill. That's what That Clicked teaches.” — Anna
System Prompt
A hidden instruction given to an AI before a conversation starts, used to set its behaviour, tone, or area of focus. You won't usually write these yourself — but they're working in the background in most AI tools you use.
Token
The unit AI models use to measure text — roughly equivalent to three-quarters of a word. Relevant because AI tools have limits on how much text they can process at once, measured in tokens. In practice you rarely need to think about this.