Where does “ptyxis” come from?

ptyxis (Latin) comes from Ancient Greek πτύξις, from Ancient Greek -σῐς, from Ancient Greek -τις, from Proto-Indo-European -tis — Derives abstract/action nouns from verb roots.

Ancestry of “ptyxis”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	πτύξις	A folding; a corrugation
2	Ancient Greek	-σῐς	"suffix forming nouns"
3	Ancient Greek	-τις	retained after dentals
4	Proto-Indo-European	-tis	Derives abstract/action nouns from verb roots

Every word from Proto-Indo-European -tis →Every word from Ancient Greek -σῐς →Every word from Ancient Greek -τις →