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1.
A baby mama's mama that is grandpaing baby mama sweet child.
Thats big grandma but don't tell little daddy
by BigMamaSweetAss October 31, 2007
3 4
 
2.
"Big grandma" is one of your two grandmothers who is the elder one. Big grandma could also be the great-grandmother.

(Think of it like "big brother; big sister" bigger as in older.)
My "big grandma" is my great-grandmother and she's older than my grandma.
by StrawberryRedHead July 29, 2011
3 9