🧠Claude Glossary

🧠 Key Concepts

A reference for the terms that come up consistently when using Claude written for people who don't want to wade through specification documents.

Token — The smallest unit Claude reads and writes, roughly ¾ of a word. "Hello world" is about 3 tokens.

Context window — Claude's working memory. Everything it can hold in mind at once: your conversation, files, and instructions.

Model — The specific version of Claude you're talking to. Haiku is fast and light, Sonnet is balanced, Opus is the most capable.

Extended thinking — Claude reasons step-by-step internally before giving an answer. Useful for complex or multi-part questions.

Hallucination — When Claude confidently states something false. It sounds certain, but the information isn't accurate.

Prompt — The message or instruction you give Claude to get a response.

System prompt — Hidden instructions set by a developer before your conversation starts. They shape Claude's tone and behavior without you seeing them.

Temperature — A setting that controls how creative vs. predictable Claude's responses are. Low = consistent and precise. High = more varied and surprising.

⚙️ Core Features

Artifact — A file or mini-app Claude creates in a side panel — a document, code snippet, chart, or interactive widget.

Project — A dedicated workspace with its own files, instructions, and chat history. Useful for ongoing work.

Memory — Claude remembers facts about you across separate conversations, so you don't have to re-explain yourself each time.

Deep research — Claude searches the web, reads multiple sources, and writes a comprehensive report — like having a research assistant.

Web search — Claude looks things up on the internet in real time to answer questions with current information.

Style — Claude learns your writing voice from samples and matches it when drafting content for you.

User preferences — Settings that tell Claude your preferred tone and format, applied automatically across conversations.

Compaction — When a conversation gets very long, Claude quietly summarizes older messages to keep things running smoothly without losing the thread.

🖥️ Products

Claude.ai — The main website and app where most people chat with Claude. Works in any browser or on mobile.

Claude Desktop — The downloadable app that unlocks deeper integrations like Cowork and Claude Code.

Cowork — Claude as a desktop agent. It can open apps, manage files, and take actions directly on your computer.

Claude Code — Claude for developers, living in your terminal and IDE. It reads your codebase, writes code, and runs commands.

Claude in Chrome — A browser extension that lets Claude see and act on the web pages you're visiting.

Claude in Excel — Claude embedded inside Excel. It can read, analyze, and build out your spreadsheets.

Claude in PowerPoint — Claude inside PowerPoint, helping you build and edit slides without leaving the app.

Claude Marketplace — A hub to discover and install connectors, plugins, and skills that extend what Claude can do.

 🤖 Agents & Automation

Connector — A live link between Claude and an external app like Gmail, Slack, or Notion, so Claude can read and act there.

MCP (Model Context Protocol) — The open standard that powers all connectors. Think of it as a universal plug for AI integrations.

Skill — A file that teaches Claude a specific workflow or best practice, so it handles a task the same way every time.

Plugin — A bundled package of skills, connectors, and commands built for a whole job role — like a Sales or HR plugin.

Sub-agent — A helper Claude that handles a parallel subtask inside a bigger job. Like delegating to a team member.

Slash command — A shortcut like /sales:call-prep that instantly triggers a preset workflow without you having to explain it each time.

Scheduled task — A recurring job Claude runs automatically on a timer, like a daily summary or weekly report.

Dispatch — Remote control for Cowork from your phone. Kick off desktop tasks via the Claude mobile app without being at your desk.

Computer use — Claude controlling your mouse and keyboard to take actions directly on your screen.

Context file — A background document Cowork reads at the start of every session — your standing instructions, preferences, or project details — so you never have to re-explain.