internal clock

American  

noun

1. biological clock.

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Etymology

Origin of internal clock

First recorded in 1955–60

Example Sentences

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

As with the Internal Clock Game, Chase was not sure how his father did this.

From Literature

A new study suggests that disruptions in the body's internal clock may be tied to a higher risk of dementia.

From Science Daily

This internal clock is directed by the brain and responds to environmental signals, especially light.

From Science Daily

A later activity peak may reflect a mismatch between the body's internal clock and environmental signals such as daylight and darkness.

From Science Daily