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1.
A frister serves both as a friend and a sister. This word is most commonly used between twins, for they are usually incredibly close and are both friends and sisters. A frister is the ultimate companion who you may share inside jokes with, make lunches for, and watch ridiculous movies with.
Hey frister lets go catch an uber ridiculous movie, I'll make you a nice lunch with a home made granola bar in it.
by Shananigans333 April 06, 2009
 
2.
a friend who is like a sister, and may be a member of your framily!
they became fristers when they siblings started dating. they were part of the framily

they were like fristers after a short time as they got on as well as sisters
by Chloeoc August 11, 2008