Where does “stéréo-” come from?

stéréo- (French) comes from Ancient Greek στερεός, from Proto-Indo-European ster- — sterile, infertile.

stéréo- (French): stereo-

Definitions

Step	Language	Word	Meaning
1	Ancient Greek	στερεός	firm, solid, rigid; standard, of full value;...
2	Proto-Indo-European	ster-	sterile, infertile

stéréo- — Etymology, Origin & Word History | Etymology Explorer