internal clock

American  

noun

1. biological clock.

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Etymology

Origin of internal clock

First recorded in 1955–60

Example Sentences

See Examples For:

internal clock

Her internal clock, built over millions of years of evolution to tune human biology to the rising and setting of the Sun, is insisting it is morning.

From BBC ● Jul. 19, 2026

During adolescence, the body's internal clock naturally shifts later, meaning teenagers tend to feel alert later at night than adults do.

From Science Daily ● Mar. 11, 2026

My internal clock wherever I am just knows it’s 4 p.m. and I get a little sad.

From Los Angeles Times ● Jul. 25, 2025

You really have to be thoughtful of your act structures and that internal clock.

From Salon ● Aug. 12, 2024

Dad had jumbled my internal clock, thanks to our late-night marathon of Doctor Who—my favorite episodes with the brilliant and brave Martha Jones.

From "Sir Fig Newton and the Science of Persistence" by Sonja Thomas