/ ˈfiːdbæk; NAmE / noun [ U ]
1.
advice, criticism or information about how good or useful sth or sb's work is :
I'd appreciate some feedback on my work.
The teacher will give you feedback on the test.
We need both positive and negative feedback from our customers.
2.
the unpleasant noise produced by electrical equipment such as an amplifier when some of the power returns to the system