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 Unfortunately, these habits constantly mess up your inner biological clock, called the circadian system. Jade Wu Savvy Psychologist, Scientific American, "How to Survive as a Night Owl in a 9-to-5 World," 27 Jan. 2020 Changes in biological clocks or circadian rhythms contribute to sleep deficiency. Jennifer Earl, Fox News, "How space can change the human body," 10 Jan. 2018 The biological clock of teens is shifted, Dr. Mary Carskadon, director of the Sleep and Chronobiology Research Lab at EP Bradley Hospital, told CNN. Madeline Holcombe, CNN, "Like it or not, science backs up your teen's love of the snooze button," 17 Oct. 2019 Known as human-centric lighting, it is inspired by research into how the various wavelengths of light regulate the body’s circadian rhythm, the biological clock that prepares us to work during the day, then relax in the evening., "Are healthy light bulbs the next bright idea? - The Boston Globe," 11 Nov. 2019 Ticking away at the molecular level, the biological clock is entrained — or set — by exposure to sunlight and darkness. Washington Post, "Science Says: How daylight saving time affects health," 31 Oct. 2019 Waking before dawn might throw your biological clock off compared with someone who woke up to sunshine. Eva Frederick, Science | AAAS, "Here’s how skimping on sleep can change your appetite," 17 Oct. 2019 The busiest years of a researcher’s life are in her 20s and 30s, which corresponds with the time her biological clock is ticking most loudly. Melinda Wenner Moyer, Scientific American, "Motherhood, Not Discrimination, May Account for the Gender Gap in Tenure-Track Science Jobs," 1 June 2012 Although, studies have shown that lower intensity light sources could potentially be used to reset the biological clock for some people. Allen Kim, CNN, "Helpful tips to combat those seasonal blues," 3 Nov. 2019

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.

See More

First Known Use of biological clock

1941, in the meaning defined above

Keep scrolling for more

Learn More about biological clock

Time Traveler for biological clock

Time Traveler

The first known use of biological clock was in 1941

See more words from the same year

Statistics for biological clock

Cite this Entry

“Biological clock.” Dictionary, Merriam-Webster, Accessed 13 Jul. 2020.

Keep scrolling for more

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).


See Definitions and Examples »

Get Word of the Day daily email!

Test Your Vocabulary

Words for Summer: A Quiz

  • a closeup of a sunflower
  • Which of the following words means “of or relating to summer”?
Spell It

Can you spell these 10 commonly misspelled words?


Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!