An Etymological Dictionary of Astronomy and Astrophysics

A device that compares the measured property of an object
(position, shape, color, brightness) with a standard.
→ blink comparator.

Etymology (EN): L.L. comparator “comparer,” from compara, → compare,

• -tor suffix forming personal agent nouns, cf. Gk. -tor, Skt.
  -tar.

Etymology (PE): Hamsanjgar, agent noun from hamsanjidan→ comparison.