D defs.my
Entry 1 sense Webster, 1913

Collimate

· Col·li·mate · IPA /ˈkɒlɪmeɪt/
01 v. t. To render parallel to a certain line or direction; to bring into the same line, as the axes of telescopes, etc.; to render parallel, as ray…
imp. & p. p. Collimated; p. p. & vb. n. Collimating
  1. 1.
    To render parallel to a certain line or direction; to bring into the same line, as the axes of telescopes, etc.; to render parallel, as rays of light.(Physics & Astron.)
Phrases & compounds
Collimating eyepiece — an eyepiece with a diagonal reflector for illumination, used to determine the error of collimation in a transit instrument by observing the image of a cross wire reflected from mercury, and comparing its position in the field with that of the same wire seen directly.
Collimating lens — a lens used for producing parallel rays of light.