Where does “circadian” come from?

Circadian derives from Latin circa meaning "around" and Latin dies meaning "day," ultimately tracing to Proto-Indo-European dyew- meaning "to shine."

circadian (English): of, relating to, or showing rhythmic behaviour...

Definitions

  1. of, relating to, or showing rhythmic behaviour...

Ancestry of “circadian”, step by step

circadian traces back through 3 separate lines of ancestry.

via Latin diēs

StepLanguageWordMeaning
1LatindiēsA day, particularly
2Proto-Italicdjēmaccusative singular of *djous
3Proto-Italic*djous
4Proto-Indo-Europeandyḗwssky, heaven; sky god
5Proto-Indo-Europeandyéwssky, heaven
6Proto-Indo-Europeandyew-to be bright; sky, heaven

via Latin circā

StepLanguageWordMeaning
1Latincircā
2Latincircumabout, around; in a circle, all around, on both...
3Latincircusa circular line or orbit; circle, ring; a...
4Ancient Greekκρίκοςring
5Proto-Indo-European(s)ḱer-dung, manure, filth; manure, dung, filth

via French circadien

StepLanguageWordMeaning
1Frenchcircadiencircadian

Words derived from “circadian

Every word from Proto-Indo-European dyew-Every word from Proto-Indo-European dyéwsEvery word from Proto-Indo-European dyḗws
circadian — Etymology, Origin & Word History | Etymology Explorer