biological clock

American  

[bahy-uh-loj-i-kuhl klok] / ˈbaɪ əˌlɒdʒ ɪ kəl ˈklɒk /

noun

Physiology.

1. Also called body clock.  an innate mechanism of the body that regulates its periodic cycles or biorhythms, such as the sleep-wake cycle.

2. an innate mechanism regulating the passage of an organism through the natural stages of its life, especially with reference to the reproductive stage of a woman's or man's life or the approaching end of this stage.

   My biological clock is ticking, but I don't feel ready to have kids!

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biological clock British  

noun

1. an inherent periodicity in the physiological processes of living organisms that is not dependent on the periodicity of external factors

2. the hypothetical mechanism responsible for this periodicity

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biological clock Scientific  

/ bī′ə-lŏj′ĭ-kəl /

1. An internal system that controls an organism's circadian rhythms, the cycles of behavior that occur regularly in a day. In mammals, the biological clock is located near the point in the brain where the two optic nerves cross. In many birds, the biological clock is located in the pineal gland. In protists and fungi, the individual cells themselves regulate circadian rhythms.

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biological clock Cultural  

1. The innate rhythm of behavior and body activity in living things. A twenty-four-hour cycle of body activity, which operates in some organisms, is called the circadian rhythm.

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Discover More

Although the term biological clock refers to all innate timing mechanisms, it is often used when describing certain body functions that are subject to this rhythm, such as the loss of fertility with age.

Etymology

Origin of biological clock

First recorded in 1950–55

Example Sentences

The more blue-white tones in the lighting, and the brighter it is, the more it helps support our circadian rhythms—the biological clocks inside our cells that drive our cycles of sleepiness and wakefulness.

From The Wall Street Journal

Other behaviors that help regulate your biological clock include having a consistent eating schedule and not eating too late, exercising regularly, getting some morning sunlight and avoiding blue light in the evening.

From Seattle Times

But the biological clock in sports, as in life, is finite — and ever more so in the NFL.

From Seattle Times

Dear Amy: I just had to write in response to "Can't Wait Forever," who is about to turn 35 and has a ticking biological clock.

From Washington Post

The team members followed their biological clocks to know when to wake up, go to sleep and eat.

From Seattle Times

Related Words

• circadian rhythm