Feedback / Comment / comments / Piece / item of feedback
UsageFeedback is normally uncountable. Use comments for countable observations, or pieces or items of feedback when you need to count feedback.
Feedback
Use when
You mean reactions or evaluative information collectively.
Example
“We received helpful feedback from frontline teams.”
Comment / comments
Use when
You mean one or more countable observations or responses.
Example
“The reviewer left three comments on the draft.”
Piece / item of feedback
Use when
You need to count an individual point of feedback.
Example
“One item of feedback concerned the approval timeline.”
Quick check
a feedback, two feedbacks, many feedbacks
Usage note