What Is a Prompt in AI? Definition & Examples

A prompt is the text you send to an AI model to get a response. Think of it as a conversation starter — you provide the input, and the model generates a completion (its response).

Prompts vs. Completions

The distinction matters:

• Prompt: What you write — the question, instruction, or context you provide
• Completion: What the model generates — its response based on your prompt

Prompt:     "Explain photosynthesis in one sentence."
Completion: "Photosynthesis is the process by which plants convert
             sunlight, water, and CO₂ into glucose and oxygen."

Why Prompts Matter

The quality of your prompt directly determines the quality of the AI’s response. A vague prompt gets a vague answer. A specific, well-structured prompt gets a focused, useful response.

The rest of this course will teach you techniques to write better prompts — starting with the simplest approach and building up to advanced strategies.