n.

1. 【电子】【生】反馈；（信息等的）返回；反馈的信息
2. （新心理疗法）一个人对另一个人言行的反应

n.

1. information given in response to a product, a person's performance of a task, etc., used as a basis for improvement.
2. the modification or control of a process or system by its results or effects.
3. the return of a fraction of the output of an amplifier, microphone, or other device to the input, causing distortion or a whistling sound.