biological clock

== English == === Noun === biological clock (plural biological clocks) (biology) Any of several mechanisms that regulate the periodicity of biological functions, such as the circadian rhythm. Synonym: body clock 2005 US Department of Health - Your guide to healthy sleep Your biological clock is actually a tiny bundle of cells in your brain that responds to light signals received through your eyes. (figuratively) The perceived time limit of human fertility, especially for women, evoking pressure to conceive children before reproductive ability declines with age. Her biological clock is ticking. ==== Derived terms ==== ==== Translations ==== === See also ===