![backsight backsight](https://www.tekportal.net/wp-content/uploads/2019/01/backsight-9335.jpg)
noun Surveying.
- a sight on a previously occupied instrument station.
- (in leveling) the reading on a rod that is held on a point of known elevation, used in computing the elevation of the instrument.
noun
- the sight of a rifle nearer the stock
- surveying a reading taken looking backwards to a previously occupied stationCompare foresight (def. 4)