From Wiktionary, the free dictionary
From Middle High German -īe.
־ײַ • (-ay) f or n
- Place where characteristic activity is conducted.
- בעקער (beker, “baker”) + ־ײַ (-ay) → בעקערײַ (bekeray, “bakery”)
- Used to create abstract nouns denoting a state, condition, or quality.
- דאָקטער (dokter, “doctor”) + ־ײַ (-ay) → דאָקטערײַ (dokteray, “medicine (profession)”)