Translation:Your mother's sister is your aunt.
Why is "Your mom's sister" wrong? It only accepts "Your mother's sister".
This is really weird cuz I've only ever heard mom's sister pronounced as मासी (maasee).
Correct word is मौसी but many people use मासी instead, just like चाचू/मामू instead of चाचा/मामा।
I've heard that a lot too. I think it's spelled like 'mausi' but pronounced like 'maasi', because I've never heard anyone say 'mausi'.