Dictionary.com
definitions
  • synonyms

circadian

[sur-key-dee-uh n, -kad-ee-, sur-kuh-dee-uh n]
See more synonyms for circadian on Thesaurus.com
adjective
  1. noting or pertaining to rhythmic biological cycles recurring at approximately 24-hour intervals.
Show More

Origin of circadian

1955–60; < Latin circā about + di(ēs) day + -an
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for circadian

Contemporary Examples


British Dictionary definitions for circadian

circadian

adjective
  1. of or relating to biological processes that occur regularly at about 24-hour intervals, even in the absence of periodicity in the environmentSee also biological clock
Show More

Word Origin

C20: from Latin circa about + diēs day
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for circadian

adj.

coined 1959 from Latin circa "about" (see circa) + diem, accusative singular of dies "day" (see diurnal). The original use is in circadian rhythm.

Show More
Online Etymology Dictionary, © 2010 Douglas Harper

circadian in Medicine

circadian

(sər-kādē-ən, -kădē-, sûr′kə-dīən, -dē-)
adj.
  1. Relating to biological variations or rhythms with a cycle of about 24 hours.
Show More
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.