Reverse operation Meaning, Definition & Usage

Definitions
  1. (Math.), an operation the steps of which are taken in a contrary order to that in which the same or similar steps are taken in another operation considered as direct; an operation in which that is sought which in another operation is given, and that given which in the other is sought; as, finding the length of a pendulum from its time of vibration is the reverse operation to finding the time of vibration from the length.

Webster 1913