A prompt is the question or instruction a user types into an AI assistant to get a response. In the context of AI visibility, a prompt is the unit of demand, the equivalent of a search query, and the thing you track to see whether your brand appears in the answer.
For brands, prompts are the foundation of measurement. The prompts you choose to track define what you are measuring, so they need to reflect the real questions buyers ask at each stage, from broad category questions to direct comparisons. A visibility result is only as meaningful as the prompt set behind it, which is why selecting representative prompts is the first step in any AI visibility program.