Learn how to say Collimation correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word collimation:
(physics) the adjustment of the line of sight of an optical instrument
collimate (ˈkɒlɪˌmeɪt Pronunciation for collimate )
to adjust the line of sight of (an optical instrument)
to use a collimator on (a beam of radiation or particles)
to make parallel or bring into line