look up any word, like the eiffel tower:
 
1.
A woman that is one level above a jump off but always a step below the wife, wifey, girlfriend. A side bitch must know her part. She does not get holiday's, birthday's (other than her own). While he may meet your family. You will never meet his.
A side bitch is a woman who will have sex on Feb. 1-13 and spend Valentines day alone.
by class09 January 30, 2009
 
2.
Usually a girl best friend that's pretty close that you wanna fuck when you have a girlfriend. Most commonly an ex-best friend/friend of your girlfriend.
Tom: Damn Tracy is pretty hot i wanna make her my side bitch
Lance: Dude what about your girlfriend Hannah?
Tom: She doesn't need to know about my side bitch
by dic...tionary October 27, 2014
 
3.
like a sidekick to a complete bitch.
She's like Leah's total SIDEBITCH.
by XxLOL_iLY123xX February 01, 2009