The practice of designing and refining prompts to reliably produce high-quality outputs from a model.
Friendly Description: Prompt engineering is the craft of writing prompts in a way that gets the best possible answers from an AI. It's a bit like learning how to brief a new assistant: with practice, you figure out what context to share, how to phrase requests, and how to give examples so the work comes back exactly the way you want it.
Example: A marketing manager who wants AI to draft social posts in their brand voice might develop a careful prompt template: a description of the brand, a few examples of past posts, instructions about tone and length, and then the topic for today. That structured prompt produces much better results than just typing "Write a tweet."