biological clock


: an inherent timing mechanism in a living system that is inferred to exist in order to explain the timing or periodicity of various behaviors and physiological states and processes

Example Sentences

Recent Examples on the Web In addition, nearly half of the adults in the study reported social jet lag – a bad fit between the sleep timing preferred by a person’s inner biological clock and the one dictated by society. Sandee Lamotte, CNN, 8 Nov. 2022 Lacking regularity in your sleep schedule can lead to a phenomenon called social jet lag, which refers to a mismatch between an individual’s biological clock and their social clock, says Dr. Dubar. Alex Janin, WSJ, 25 May 2022 Additionally, working late hours in bed can negatively affect your biological clock due to your laptop screen emitting blue light that suppresses melatonin. Amiah Taylor, Fortune, 12 May 2022 This pushes the biological clock forward an hour as well. Paul Leblanc, CNN, 9 Apr. 2022 Some scientists suggest that your biological clock gets out of sorts. Frank Witsil, Detroit Free Press, 8 Mar. 2022 Scientists know that white light enriched with blue wavelengths effectively helps synchronize the body’s biological clock, which is hugely influential on things like memory, cardiovascular function, and sleep quality. Erin Berger, Outside Online, 30 July 2014 In fact, there was one study that involved a year-long administration of a cocktail of different drugs that appeared to turn back the biological clock by some months, maybe more than a year. Robin Pomeroy, Scientific American, 14 Dec. 2021 With her own biological clock ticking, Alma is an emotional wreck. Angela Dawson, Forbes, 20 Sep. 2021 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'biological clock.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History

First Known Use

1941, in the meaning defined above

Time Traveler
The first known use of biological clock was in 1941

Dictionary Entries Near biological clock

Cite this Entry

“Biological clock.” Dictionary, Merriam-Webster, Accessed 5 Dec. 2022.

Kids Definition

biological clock


: a mechanism that exists in living things and controls the timing of behaviors and bodily functions which occur in cycles

Medical Definition

biological clock


: an inherent timing mechanism in a living system (as a cell) that is inferred to exist in order to explain various cyclical behaviors and physiological processes

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