Where does “cydonin” come from?

cydonin (English) comes from Translingual Cydonia, from Latin cydōnia, from Ancient Greek Κυδωνία — Cydonia; quince-tree.

cydonin (English): A mucilaginous substance extracted from the seeds...

Definitions

Step	Language	Word	Meaning
1	Translingual	Cydonia	—
2	Latin	cydōnia	—
3	Ancient Greek	Κυδωνία	Cydonia; quince-tree

cydonin — Etymology, Origin & Word History | Etymology Explorer