Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
An external stimulus or cue, such as daylight or a regularly repeated occurrence, that serves to regulate an organism's biological clock.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
zeitgeberA factor in the environment that has periodicity and is capable of synchronising the endogenous circadian rhythm into a 24-hour cycle. Without zeitgebers, the free-running human clock has long been believed to be about 25.3 hours; more recent work by Charles A. Czeisler MD, PhD, pegs the internal human clock at 24 hours and 11 minutes, ±16 minutes.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
zeitgeberZeit, German, time, geber, keeper A factor in the environment with a periodicity, capable of synchronizing the endogenous circadian rhythm into a 24-hr cycle; without zeitgebers, the free-running human clock is 25.3 hrs. See Circadian rhythm, Jet lag, Shift work, Sleep disorders. Cf REM sleep.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
zeitgeber(tsīt′gā″bĕr, zīt′) [Ger. Zeitgeber, timekeeper]
Any of the mechanisms in nature that keep internal biological clocks synchronized (entrained) with the environment. Zeitgebers can be physical, involving light or temperature (e.g., sunrise, sunset), or social, involving regular activities (e.g., consistent mealtimes).
Medical Dictionary, © 2009 Farlex and Partners