[f. BACK adv.]
a. In Surveying, a ‘sight’ or reading taken backwards, or towards the point of starting. b. The sight of a rifle nearer the stock.
1860. All Y. Round, No. 71. 501. The back or elevating sight.
1867. Marsh in N. Y. Nation, 9 May, 373. A backsight is a sight or reading taken backwards; that is, in a direction opposite to that in which the levelling party is proceeding.
1880. Times, 18 Oct., 4/3. In using the rifle a native rarely avails himself of the foresight, and still more rarely of the backsight.
