look up any word, like the eiffel tower:
1. A female who has had sex with the same woman as a good friend. (not necessarily simultaneously)

2. When two females acknowledge having been intimate with the same male and remain on good terms, the girls are now bonded by having shared the same penis at one time or another.

3. Refers to two women who have slept with the same man.
Girl 1 "Holy shit, you slept with that guy rolando too?"
Girl 2 "Yes, but he told me i was his only one"
Girl 1 "Fuuuuuuuuuuuuuckit, were wallet sisters now"
Girl 2 "Ewwwwww! Wanna go shopping?"
Girl 1 "Like, totally"
by _RollOnDough January 20, 2012