Where does “semidiurnal” come from?

semidiurnal (English) comes from English diurnal, from Latin diurnālis, from Latin diurnus, from Latin diēs, from Proto-Italic djēm, from Proto-Italic *djous, from Proto-Indo-European dyḗws, from Proto-Indo-European dyéws — to be bright; sky, heaven.

semidiurnal (English): Twice daily; Accomplished in half a day; Flying...

Definitions

  1. Twice daily; Accomplished in half a day; Flying...

Ancestry of “semidiurnal”, step by step

semidiurnal traces back through two separate lines of ancestry.

via English diurnal

StepLanguageWordMeaning
1EnglishdiurnalHappening or occurring during daylight, or...
2Latindiurnālisdiurnal of the day; that takes place during the day
3Latindiurnusof the day; daily; day
4LatindiēsA day, particularly
5Proto-Italicdjēmaccusative singular of *djous
6Proto-Italic*djous
7Proto-Indo-Europeandyḗwssky, heaven; sky god
8Proto-Indo-Europeandyéwssky, heaven
9Proto-Indo-Europeandyew-to be bright; sky, heaven

via English semi

StepLanguageWordMeaning
1EnglishsemiA semi-detached house; A semitrailer; a...
2Englishsemi-half; partial, incomplete; somewhat, rather,...
3Latinsēmi-half
4Proto-Indo-Europeansēmihalf; partially
Every word from Proto-Indo-European dyew-Every word from Proto-Indo-European dyéwsEvery word from Proto-Indo-European dyḗws
semidiurnal — Etymology, Origin & Word History | Etymology Explorer