- collimator - a small telescope attached to a large telescope to use in setting the line of the larger one
--1 is a kind of telescope, scope
Derived form: verb collimate2 - collimator - optical device consisting of a tube containing a convex achromatic lens at one end and a slit at the other with the slit at the focus of the lens; light rays leave the slit as a parallel beam
--2 is a kind of optical device
--2 is a part of spectroscope, prism spectroscope