Where does “στερεόν” come from?

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

Ancestry of “στερεόν”, step by step

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

στερεόν — Etymology, Origin & Word History | Etymology Explorer