Latin word serenus comes from Proto-Indo-European *kseros

Detailed word origin of serenus

Dictionary entry	Language	Definition
*kseros	Proto-Indo-European (ine-pro)
serenus	Latin (lat)	(figuratively) Cheerful, glad, joyous.. Clear, fair, bright, serene, tranquil.. That clears the sky or brings fair weather.

Words with the same origin as serenus