Who is my neice's Grandma's, And her Dad (my brother 'n law) Mom To me.?

Question:

Who is my neice's Grandma's, And her Dad (my brother 'n law) Mom To me.?

Ever since my sister married my brother 'n law i've been curious on who his mom is too me. Which is my Neice's Grandma as well. But When I go to the store with her or waiting somewhere with her people ask me if they can help me and I say i'm waiting for a relative but I don't know which relative. Is she just an Inn Law thru marriage or is there an actual name for what she is to me. Just was curious if anybody knew. Thank you, for any Serious Answer's!

Best Answer - Chosen by Asker: Technically, she's nothing to you. It's nice you seem to have a good relationship with her, though. You can still say "A relative." If someone asks for specifics, just say "My brother-in-law's Mom."