Prompt has several related meanings:

When someone is prompt, they arrive or act exactly when expected. A prompt student shows up to class right when it starts, not five minutes late. If you give a prompt reply to an invitation, you respond quickly instead of waiting days. Being prompt shows respect for others' time and demonstrates reliability.

To prompt someone means to encourage them to take action or to remind them of something. A teacher might prompt a shy student to share their answer by asking an encouraging question. If you forget your line in the school play, another actor might whisper it to you as a prompt. Stage directions sometimes include prompts that tell actors when to enter or exit.

The word can also mean something that causes a reaction or serves as a starting point. A writing prompt gives you a topic or question to spark your creativity. When you see storm clouds gathering, they might prompt you to grab an umbrella. In this sense, a prompt is like a gentle push that gets something started.

The connection between these meanings is timing and action: being on time yourself, helping someone else remember, or giving the nudge that starts something happening.