A "response" is the information sent back from a server to a client after the client makes a request. When you use an API, you typically send a request to a server asking for certain data or to perform an action. The server processes that request and then sends back a response, which includes the data or information you asked for, or details about the action you wanted to be performed.
A response usually contains a status code, headers, and a body:
In simple terms, the response is how the server talks back to you, letting you know whether your request was successful and providing the information or results you need.