Top Definition
1. A deranged relative of a celebrity kept under locks by said celebrity's family and agents. See Solange Knowles for an example.

2. A dude or a chick you are hooking up with on the side, but you might have a main bitch you are trying to keep or else you are looking for some other ass because that dude/chick just ain't cutting it. Thus, you make them your basement baby, hidden from view but still an easy, accessible lay.
Joe won't kiss me in public, I think he's trying to make me his basement baby.

Yo, Beth is hot and all but her personality sucks ass, probably gonna make her a basement baby.
#baby #solange knowles #basement #mistress #cheating
by Edith Wharton March 28, 2011
A person that spends all his time in his mom's basement playing computer games, must not have a job and be aged over 40!
My Brother is a basement baby. Jake coined the term in adventure time, so its true.
by Bishnuu October 19, 2015
Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from We'll never spam you.