Define

define

Give plain definitions. One line of definition + one line of purpose. That's it.

Format

For each term:

**Term** — definition.
*Purpose:* what the thing is for.
*Example:* one concrete instance, in plain words. No code.

Multiple terms: do them as a flat list in this format. No section headers between them.

Optional extra line per term: _Avoid_: X, Y, Z. — names NOT to use for this concept. Use only when the user is establishing project-wide vocabulary discipline (e.g., editing a glossary).

Rules

• No analogies. No light bulbs, power adapters, restaurants, clocks, plumbing, lego, kitchens, USB ports, etc. Definitions, not metaphors.
• No code examples. Unless the user explicitly asks for one.
• No narrative buildup. Don't say "let me explain", "great question", or restate the term in a sentence before defining it. Lead with the bolded term and an em-dash.
• Three lines per term (four if _Avoid_ is needed). If you can't define in one line, the definition is too vague — sharpen it.
• Purpose answers "why does this exist?" — not "how do you use it?" or "what does it do internally?"
• Example is concrete and specific — one real instance, not a category. "Unix tee command" beats "any fan-out tool." Plain prose, no code blocks.
• Plain English in the definition. Don't define a term using other jargon unless that jargon was already defined in the same response or is clearly common knowledge.
• No closing summary, no "does that help?" pleasantries. End on the last definition.

When to use

• User asks "what is X?" / "define X" / "what does X mean?"
• User says "explain X" — unless they explicitly ask for examples or deeper context.
• User invokes /define X.
• User has pushed back on a verbose explanation and asked for "just the definition," "no analogies," "plain definition," or similar.

When NOT to use

• "How does X work?" → process question, not a definition. Give a normal explanation.
• "Why does X matter?" / "give me an example of X" → wants elaboration.
• Asks for a tutorial, walkthrough, comparison, or argument.

Example

User: "what's a closure?"

Response:

Closure — a function bundled with the variables from the scope where it was created. Purpose: lets a function remember data from outside its body even after that outer code has finished running. Example: a counter function that returns the next number each time you call it, by holding onto a count variable from its creator.