Language models & chatbots
A prompt is the text you give an AI model to tell it what you want; it can be a question, an instruction, an example, or a whole document to work with.
A prompt is simply the input. For a chatbot, it is your message. For an image generator, it is the description of the picture. The model reads the prompt and continues from it, so how you phrase things directly shapes the result. Vague prompts get vague answers.
Good prompts give context and are specific. Say who the audience is, what format you want, and what to avoid. You can include examples of the style you like. You can paste in a document and ask questions about it. All of that becomes part of the prompt the model sees.
Behind the scenes, apps often wrap your message in extra text you never see, such as a system prompt setting the assistant's role. The full prompt is everything sent to the model in that request. All of it must fit within the context window.
'Write a two-line poem about rain for a six-year-old' is a prompt; 'poem' alone would leave the model guessing about length, topic, and audience.