biological clock


Definition of 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

Examples of biological clock in a Sentence

Recent Examples on the Web

The cause is unknown, but cluster headaches may occur if something with the body’s biological clock is off, per the Mayo Clinic. Amy Marturana, SELF, "What Your Headaches Can Tell You About Your Health," 29 Dec. 2018 In the days after daylight saving time starts, our biological clocks are a little bit off. Brian Resnick, Vox, "Daylight saving time ends Sunday: 8 things to know about “falling back”," 2 Nov. 2018 The timetable of how her life unfolds need not adhere to a pesky biological clock. Robin Marantz Henig, WIRED, "Women May Have an Alternative to Freezing Their Eggs," 27 Mar. 2018 Patients hospitalized for more than two or three days can run into trouble because, without proper light exposure, biological clocks shift a few minutes each day. Stacey Burling,, "The era of circadian lighting in health care is dawning," 27 June 2018 Science and healthy living have extended the biological clock. Brennan Peterson,, "5 myths about infertility," 26 June 2018 When the biological clock turns kids into night owls and day sleepers. Eva Dwight, USA TODAY, "How do you get teens out of bed during the summer without fighting?," 25 June 2018 Bill Guest was about 30 when his biological clock kicked in. Nara Schoenberg, ajc, "I wanted a baby:’ Single men are increasingly having biological children via surrogacy," 17 June 2018 That means players will have to figure out how to sync their biological clocks for travel, training, and matches. Eric Niiler, WIRED, "Can PJs and Sound Sleep Lead to a World Cup Victory?," 14 June 2018

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.

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First Known Use of biological clock

1941, in the meaning defined above

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Time Traveler for biological clock

The first known use of biological clock was in 1941

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More Definitions for biological clock

biological clock


English Language Learners Definition of biological clock

: a system in the body that controls the occurrence of natural processes (such as waking, sleeping, and aging)

biological clock


Medical Definition of 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

More from Merriam-Webster on biological clock Encyclopedia article about biological clock

Comments on biological clock

What made you want to look up biological clock? Please tell us where you read or heard it (including the quote, if possible).


to move or proceed with twists and turns

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