from The American Heritage® Dictionary of the English Language, 5th Edition.

  • transitive verb To make parallel; line up.
  • transitive verb To adjust the line of sight of (an optical device).

from The Century Dictionary.

  • To bring into the same line, as the axes of two lenses or the telescope of an optical instrument; also, to make parallel, as the rays of light passing through a lens.
  • To render the line passing through the optical center of the object-glass of a telescope and the middle wire of its reticule strictly perpendicular (or sometimes parallel) to the axis on which the telescope turns: usually by the aid of a collimator, or of star-observations in reversed positions of the instrument.

from the GNU version of the Collaborative International Dictionary of English.

  • transitive verb (Physics & Astron.) 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.
  • transitive verb 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.
  • transitive verb (Optics) a lens used for producing parallel rays of light.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • verb To focus into a narrow beam or column.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • verb make or place parallel to something
  • verb adjust the line of sight of (an optical instrument)


from The American Heritage® Dictionary of the English Language, 4th Edition

[New Latin collīmāre, collīmāt-, alteration of Latin collīneāre, to aim : com-, intensive pref.; see com– + līneāre, to make straight (from līnea, line; see line).]


  • A slight vacuum is pulled behind an aluminized mylar plastic film to create a very large convex mirror to collimate the visual system in many aircraft simulators.

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  • In fact, if the particles in the jet are fast enough, they can collimate themselves quite nicely due to relativistic effects.

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  • In 2005 they used high-power ‘Luxeon’ LEDs, i.e. non-coherent sources, combined with a large Fresnel lens to collimate the non-directional light emitted, and managed two-way audio communications over a distance of 160 km (100 miles!) between mountaintops in Tasmania.

    Long-range optical communication… how much would you pay? « Skulls in the Stars

  • It was enough time to collimate a neutrino-beam and to fire it through the cases.

    Fiction snippet: A Small Dose Of The Flu

  • We collimate it so that we have a uniform beam illuminating the test piece.

    Archive 2004-04-01

  • Basically I seem to have designed a device which will collimate an extended light source.

    Make - All Discussions

  • Using a light pipe [such as fiber optic] won't help to collimate your beam, total internal reflection means that as the angle of incidence = = the angle of reflection, the light entering the pipe at random angles will exit just as randomly.

    Make - All Discussions

  • You can focus it to a point, but there's nothing you can do that will fully collimate the beam, i.e. it will always diverge.

    Make - All Discussions

  • You're going to want to collimate it, which is a way of aligning the optics.

    Astronomy Cast

  • There are two nouns morion kind of helmet, does not concern us here (it is probably from Spanish smoky quartz, has an interesting etymology: it is from a Latin word here about collimate, from an erroneous reading of Latin collineare; I wonder if there is a list somewhere of words with similar histories?


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