finder

Finder \Find"er\, n. 1. One who, or that which, finds; specifically (Astron.), a small telescope of low power and large field of view, attached to a larger telescope, for the purpose of finding an object more readily, called also a {finder telescope} or {finder scope}. [1913 Webster +PJC] 2. (Micros.) A slide ruled in squares, so as to assist in locating particular points in the field of vision. [Webster 1913 Suppl.]