[sur-key-dee-uh n, -kad-ee-, sur-kuh-dee-uh n]
- noting or pertaining to rhythmic biological cycles recurring at approximately 24-hour intervals.
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
Bright light is what keeps our circadian rhythms in good order.Fight Seasonal Affective Disorder With This New Tracker
November 7, 2014
Lighting signals your body's circadian rhythm and can have a strong effect on your mood.Change Your Sense: Biohacking for Beginners
March 18, 2014
“One of the most important things you can do for your sleep is to have a routine to keep your circadian rhythm normal,” says Suh.Can’t Sleep? Your Guide to a Better Night’s Rest
January 24, 2014
- 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
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
Online Etymology Dictionary, © 2010 Douglas Harper
circadian(sər-kā′dē-ən, -kăd′ē-, sûr′kə-dī′ən, -dē′-)
- Relating to biological variations or rhythms with a cycle of about 24 hours.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.