collimate

verb

col·​li·​mate ˈkä-lə-ˌmāt How to pronounce collimate (audio)
collimated; collimating

transitive verb

: to make parallel
collimate light rays
collimation noun

Did you know?

One might expect a science-y word like collimate to have a straightforward etymology, but that's not the case. Collimate comes from Latin collimāre, a misreading of the Latin word collineāre, meaning "to direct in a straight line." The erroneous collimāre appeared in some editions of the works of ancient Roman statesman Cicero and scholar Aulus Gellius. The error was propagated by later writers—most notably by astronomers, such as Johannes Kepler, who wrote in Latin. And so it was the spelling collimate, rather than collineate, that passed into English in the 19th century as a verb meaning "to make (something, such as light rays) parallel."

Example Sentences

Recent Examples on the Web But black holes produce their own radiation, especially high-energy X-rays and gamma-rays, which shoot out from the star in the form of tightly collimated... Newsweek, 14 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'collimate.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

Etymology

Latin collimatus, past participle of collimare, manuscript variant of collineare to make straight, from com- + linea line

First Known Use

1878, in the meaning defined above

Time Traveler
The first known use of collimate was in 1878

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Dictionary Entries Near collimate

Cite this Entry

“Collimate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/collimate. Accessed 7 Feb. 2023.

Kids Definition

collimate

verb
col·​li·​mate ˈkäl-ə-ˌmāt How to pronounce collimate (audio)
collimated; collimating
: to make (as rays of light) parallel

Medical Definition

collimate

transitive verb
col·​li·​mate ˈkäl-ə-ˌmāt How to pronounce collimate (audio)
collimated; collimating
: to make (as rays of light) parallel
collimation noun
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