Where does “hapaks legomenon” come from?

hapaks legomenon (Polish) comes from Ancient Greek ἅπαξ λεγόμενον, from Ancient Greek ἅπαξ, from Proto-Indo-European sm̥-, from Proto-Indo-European sem- — together, one.

hapaks legomenon (Polish): hapax legomenon

Definitions

hapax legomenon

Ancestry of “hapaks legomenon”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	ἅπαξ λεγόμενον	—
2	Ancient Greek	ἅπαξ	once, one time, only once
3	Proto-Indo-European	sm̥-	one; with, together
4	Proto-Indo-European	sem-	together, one

Every word from Proto-Indo-European sem- →Every word from Proto-Indo-European sm̥- →Every word from Ancient Greek ἅπαξ →