range finder

or range·find·er

noun

any of various instruments for determining the distance from the observer to a particular object, as for sighting a gun or adjusting the focus of a camera.

Origin of range finder

First recorded in 1870–75

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for rangefinder

Historical Examples of rangefinder

"Target—range one eight zero four, azimuth two four oh, elevation one oh seven," the rangefinder reported.
A Question of Courage
Jesse Franklin Bone
"Action imminent," Chase ordered, and the rangefinder took up his chant.
A Question of Courage
Jesse Franklin Bone

British Dictionary definitions for rangefinder

rangefinder

noun

an instrument for determining the distance of an object from the observer, esp in order to sight a gun or focus a camera
another word for tacheometer

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012