Feedback (noun)

1. Information about reactions to a product, a person's performance of a task, etc. which is used as a basis for improvement.
2. The return of a part of the output of a process or system to the input, especially when used to maintain performance or to control a system or process.

Origin:

Early 20th century: from feed + back.

Examples:

1. I received feedback on my performance.
2. The company asked for customer feedback on their new product.
3. The teacher gave feedback on the student's paper.
4. The microphone had feedback from the speakers.
5. The website has a feedback section for users to leave comments.