Prompt engineering
The practice of writing prompts so a model reliably returns what you actually want — mostly clarity, not tricks.
Prompt engineering is the skill of phrasing a prompt so the model produces the result you intended, consistently, without many rounds of correction. Despite the name it is rarely about secret phrases; it is mostly the disciplined work of stating the task, the audience, the format, and the constraints clearly.
It matters because models are literal and cannot read intent. The same model, given a vague prompt and a precise one, produces markedly different work — so prompt engineering is often the cheapest way to improve output, well before reaching for a bigger model or fine-tuning.