Where does “Μέγᾰρᾰ” come from?

Μέγᾰρᾰ (Ancient Greek) comes from Ancient Greek μέγᾰρον.

Ancestry of “Μέγᾰρᾰ”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	μέγᾰρον	—

Μέγᾰρᾰ — Etymology, Origin & Word History | Etymology Explorer