biological clockbiological clock
any of the various natural cycles in organisms that are related to the tides, sun, moon, light, temperature, etc. and that control breeding, feeding, migration, etc.: often used fig., as in ref. to the years during which a woman is able to bear children
- 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.