Circadian
/sɜːrˈkeɪdiən/noun
Relating to the roughly 24-hour cycle of biological activity in living organisms.
Did you know?Circadian was coined in the 20th century from Latin roots, but the idea it names is ancient: living things were observed to keep time with the Sun long before scientists could explain the mechanism.
Etymological Timeline
Latin roots
Latin
circā
“around, about”
Latin roots
Latin
diēs
“day”
20th Century
English
circadian
“coined to describe a biological rhythm lasting about a day”
Modern English
English
circadian
“pertaining to the daily biological cycle in organisms”
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