The grandmother of your biological child, when the child isn't legally yours. Put simply: the mother of a baby
momma.
A famous example of a baby momma momma in pop culture is
Ms. Jackson, from the song of the same name written by
Outkast.
1) I brought my kid to my baby momma
momma's house. He loves his grandma.
In pop culture:
"Yeah, this one right here goes out to all the baby's mommas, mommas... mommas, mommas, baby mommas" - Outkast, "
Ms. Jackson"
"I rap so vicious but I talk so politely / Never met a baby momma momma who don't like me" -
J. Cole, "The Autograph"