biological clock

noun

: 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

Plants and animals keenly sense the diminishing light, which acts as a master biological clock that triggers changes such as migration, shifting hormone levels and winter coat growth. — Charles Seabrook, AJC.com, 1 Aug. 2026

This ideal amount of sleep was associated with less ageing, as measured by organ-specific biological clocks. — Chas Newkey-Burden, TheWeek, 31 July 2026

What circadian rhythms actually are Circadian rhythms exist in most living organisms and are regulated by light, behavior and a biological clock built from genes in cells throughout the body. — Hanna Wickes, Sacbee.com, 21 July 2026

Our innate cycle is not exactly 24 hours, so biological clocks must reset daily to sync with Earth’s rotation. — Hanna Wickes, Charlotte Observer, 21 July 2026

Word History

First Known Use

1941, in the meaning defined above

Rhymes for biological clock

• aftershock
• antiknock
• arawak
• hollyhock
• interlock
• manioc
• shuttlecock
• tomahawk
• weathercock
• alcock
• beanstalk
• bedrock

Kids Definition

biological clock

noun

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

Medical Definition

biological clock

noun

: 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