I’m really bad at mapping family relationships.
My mom and this other woman had the same grandfather. What Relationship is this other Woman to me? Also what relationship would this woman’s granddaughter be to me?
Re: What Relationship am I to a woman that shares a grandparent with my mom?
She should be your sister and the grand daughter be your grandchild?
I think.
Re: What Relationship am I to a woman that shares a grandparent with my mom?
she is ur aunt and her grand daughter is ur niece............
Re: What Relationship am I to a woman that shares a grandparent with my mom?
she is your mom’s first cousin and your 2nd aunt..Therefore, her niece is technically your granddaughter???
ok I just confused myself too 
Lets break it up:
Grandfather
: :
: :
: :
Your mom the lady = cousins
The lady is your moms cousin = your aunt
your aunt has a kid = your cousin
your aunt has a kid who has a kid = your niece
that makes sense now pheww
Re: What Relationship am I to a woman that shares a grandparent with my mom?
^Yup.
Re: What Relationship am I to a woman that shares a grandparent with my mom?
other woman is your aunt (khala) and you are also aunt/uncle of her granddaughter .
Re: What Relationship am I to a woman that shares a grandparent with my mom?
Tea1234 has done it right if you are talking about Pakistani relationships, as often your first cousins are like your brothers and sisters but Western wise it would be:
Your mum and the lady = 1st cousins
The lady is therefore your 1st cousin once removed
your aunt's kid = your 2nd cousin
your aunt's kid's kid = your 2nd cousin once removed
This is because the lady is not your mum's sister.