Longman Dictionary of Contemporary English homepage

Date: 1900-2000
Language: Latin
Origin: circa 'around, about' + dies 'day'

circadian

 adjective
     
Related topics: Chronology
cir‧ca‧di‧an [only before noun] technical
TMCHBH relating to a period of 24 hours, used especially when talking about changes in people's bodies:
the body's circadian rhythm
Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.

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