Where does “phāsiānus” come from?

phāsiānus (Latin) comes from Ancient Greek φασιανός, from Ancient Greek Φᾱσῐᾱνός, from Ancient Greek Φᾶσῐς — Phasis.

Ancestry of “phāsiānus”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	φασιανός	pheasant
2	Ancient Greek	Φᾱσῐᾱνός	Phasian
3	Ancient Greek	Φᾶσῐς	Phasis