Glossary

LLM (Large Language Model)

The technology behind ChatGPT and Claude. A program trained on enormous amounts of text that learns to predict what should come next — turns out that's enough to write, summarize, explain, and reason.

Prompt

The thing you type to the AI. Better prompts → better answers. Most of this site is about writing better prompts.

Hallucination

When AI invents something — a fact, a quote, a citation — and presents it confidently. The fix: verify anything that matters.

Context

The information you give the AI to work with — facts about you, the situation, the goal. The single biggest lever for better answers.

Token

A small chunk of text (roughly 4 characters or ¾ of a word). AI is paid and limited by tokens. You don't need to count them — just know that "too long" is a real constraint.

Context window

How much text the AI can "see" at once. Modern AIs can read whole books at a time, but very long chats can still lose track of what you said up top.

Model

A specific version of an AI. Companies release new ones constantly (you'll see names like GPT-5, Claude Sonnet, Gemini, etc.). Newer is usually smarter, but not always cheaper or faster — and for most family tasks, last year's model is still plenty.

API

A way for software to talk to AI directly (instead of through a chat website). Comes up when you want to build something that uses AI, like an app or automation.

RAG (Retrieval-Augmented Generation)

When an AI looks things up in a specific document or database before answering. It's how AI products give answers grounded in real, current data.

Fine-tuning

Customizing a model on specific examples so it gets better at a narrow task. Usually overkill for personal use — better prompting does most of the work.

System prompt

A "behind the scenes" instruction that shapes how the AI behaves in a chat — like "you are a helpful tutor for a 6th grader." Some apps let you set this; most chats just have a default.

Multimodal

An AI that can handle more than text — images, audio, sometimes video. Photo-of-a-receipt → typed total is a multimodal task.

Agent

An AI that can do multi-step things on its own — not just answer, but browse the web, fill out forms, book things, draft and send. Most major AI apps now have some form of this (deep research, task mode, computer use). Useful, but worth supervising — give it small jobs before big ones.

Open source / open weights

AI models you can download and run yourself. Mostly relevant if you're technical. Less relevant for most family use.

Cloud / on-device

Whether the AI runs on someone else's computer (cloud — ChatGPT, Claude) or on your own (on-device — like Apple Intelligence). On-device is more private; cloud is usually more capable.

Privacy mode / temporary chat

A setting that tells the AI service not to use your conversation to train future models. Use it when sharing anything you don't want stored.

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