usually used as an insult or joke.
man1: dude you ugly!
man2: yo mama!
Your baby mama is when you accidentally get a woman pregnant-- oopsie daisy-- but you two aren't together. If a pregnancy is the result of a one-night-stand, she's your baby mama and you are her baby daddy. Sometimes you two can agree to raise the child as single parents, but in cases like How I Met Your Mother (Barney's mom), the baby mama will raise the kid on her own.
Anyone: Wait, who's Delilah?
Me: she's my baby mama.
(noun) (plural)
Mature women, of a certain age
When I see Mutation Mamas, I think of silver-haired wisdom.
(noun) (plural)
Very old ladies.
Notice that all these Mutation Mamas are playing those slot machines?