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Related to biological clock: circadian rhythm
1. An internal mechanism in organisms that controls the periodicity of various functions or activities, such as metabolic changes, sleep cycles, or photosynthesis.
a. The time period during which a person who desires to have a biological child, especially a woman approaching the decline of reproductive capability, is still able to do so.
b. The capacity to be fertile, especially in such a woman: She was eager to have a child before her biological clock stopped working.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. (Biology) an inherent periodicity in the physiological processes of living organisms that is not dependent on the periodicity of external factors
2. (Biology) the hypothetical mechanism responsible for this periodicity
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
1. an innate mechanism of the body that regulates its rhythmic and periodic cycles, as that of sleeping and waking.
2. such a mechanism perceived as inexorably marking the passage of one's youth and esp. one's ability to bear children.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
An internal system of organisms that controls the cycle of various functions, such as sleep cycles in mammals and photosynthesis in plants. See Note at circadian rhythm.
The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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|Noun||1.||biological clock - an innate mechanism in living organisms that controls the periodicity of many physiological functions|
mechanism - a natural object resembling a machine in structure or function; "the mechanism of the ear"; "the mechanism of infection"
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