Where does “աբբայ” come from?

աբբայ (Old Armenian) comes from Ancient Greek ἀββα, from Aramaic אבא, from Proto-Semitic ʔabw-, from Proto-Afroasiatic ʔab- — father.

Ancestry of “աբբայ”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	ἀββα	father; title of respect given to abbots
2	Aramaic	אבא	father, ancestor, progenitor; teacher; chief,...
3	Proto-Semitic	ʔabw-	father
4	Proto-Afroasiatic	ʔab-	father