Definition of collimate
: to make (as light rays) parallel
collimationplay \ˌkä-lə-ˈmā-shən\ noun
collimate was our Word of the Day on 04/11/2014. Hear the podcast!
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 collimare, a misreading of the Latin word collineare, meaning "to direct in a straight line." The erroneous collimare 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.
Origin and Etymology of collimate
Latin collimatus, past participle of collimare, manuscript variant of collineare to make straight, from com- + linea line
First Known Use: 1878
Learn More about collimate
Seen and Heard
What made you want to look up collimate? Please tell us where you read or heard it (including the quote, if possible).