Where does “τροπαί” come from?

τροπαί (Ancient Greek) comes from Ancient Greek τροπή, from Ancient Greek -ή, from Ancient Greek -ᾱ, from Proto-Indo-European -éh₂.

Ancestry of “τροπαί”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	τροπή	a turning; turning away the enemy, a rout;...
2	Ancient Greek	-ή	suffix of feminine nouns in the [[Appendix:Ancient Greek first declension
3	Ancient Greek	-ᾱ	nominal suffix
4	Proto-Indo-European	-éh₂	—