Young college female, often times a member of a sorority, who spends an
excessive amount of time having sex with brothers of a
fraternity.
the term derives from
fraternity + mattress, because the slut spends so much time under brothers that she might as well be their bed.
"Bro, you see that frattress
over there? Yeah, the one on top of the table. I'm gonna do work and put her to use tonight."
"So, I was banging this frattress
the other night, and after we got done she told me not to tell any of my brothers. You know she's just gonna tell those other
sorostitutes how awful of a guy I am."