Where does “-ico” come from?

-ico (Latin) comes from Latin -ō, from Proto-Indo-European -ō — Derives nouns from roots.

Ancestry of “-ico”, step by step

Step	Language	Word	Meaning
1	Latin	-ō	—
2	Proto-Indo-European	-ō	Derives nouns from roots

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