A common term used around most recently around South Florida but has spread to many other influential areas of the world. It refers to a person who, by law, is considered to be a step-sister; however often times thought of by one (or both parties) to be more of a true sister.
Guy 1: "Dawg
why was you all up in that girl's face last nght?"
Guy 2: "it's totally cool bra
, that's my stepis... we're like almost related by blood"