1 definition by JM & VP

Top Definition
Short for "stuck-in-between". An acronym for a group of mature and attractive women who are younger than than the usual age limit for a MILF, yet old enough for proper recognition.

Typical age range for a SIB is between 25 and 29, but there have been reported SIB sightings in women as old as 32.
My friends and I decided to hit up this cougar bar looking for some older women, but instead the bar was filled with SIB's.

Dude, did you just see how hot that SIB was, she was perfect!

SIB Conversation (Actual):
Young Man: Hey girls, how old are you?

Attractive Busty Woman and friend: Ummm...26?

YM: Wow that's perfect, you guys are just what we were looking for, SIBs!
by JM & VP November 21, 2010

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