Meaning of Backsight
Noun / বিশেষ্য / संज्ञा
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.
the sight of a rifle nearer the stock
(surveying) a reading taken looking backwards to a previously occupied station Compare foresight (sense 4)