Compensator

Noun

1. A party or thing which compensates, pays or otherwise provides a compensation
2. Any device used to compensate for something, notably to achieve a better balance.
3. A building control device used to deliver the compensation relationship or curve between the air temperature outside a building and the temperature of water or air provided to spaces or zones within the building for purposes of heating or cooling.

   "Compensators ensure less heat is provided to a room on a warmer day. They may be implemented mechanically, electronically or in software."

4. One of several small magnets placed in the binnacle to neutralize the effect of the ship's metal on the compass