A best friend that you can call sis-sis instead of sis. Female version of brobro. Guys can have a best friend that is a girl that you can call sis-sis and nothing is going on or no one is going out.. Normally if you are best friends you can treat her like a real sister. You can love her like a real sister say I love you like you say to a real sister. Basically best friends.
Jason: Wow Chelsea, we have been friends for years now and I proud to call you my sis-sis.

Chelsea: Thanks Jason! Can I call you brobro?

Jason: Sure sis-sis.

Chelsea: Love ya brobro.

Jason: Love ya sis-sis.
by Thekidwhoisakidthatgoestomps January 25, 2011
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a philosopher of sorts. looks into a mirror and will see many reflections.

resembles a chilly philly dip; sweet and TANGY.

yo i'm si-si. LIKE A DAISEY! give me shit and i'll shit on your face. verbal diarrhoea type shit.
by lawren August 01, 2006
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Short for the word “sister” but also just an answer to any question ever.
Susan: “how was your weekend?”
Janet: “sis...”
Susan: “omg sis what’s the tea sis—spill!”
Janet: “sis!”
Susan “sis”
—and so on and so forth until Antichrist comes and the world is over
by Theworldisflat.edu August 03, 2018
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Short for sister, commonly used as a term of endearment to friends in urban new york/jersey areas
by Caroline Might Fine November 14, 2016
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suck it everyday.

perfect for awkward silence moments; a reason for people to hate you for.
person 1: sup foo?
person 2: ....
person 1: huh?
person 2: well um...
person 1: sied nub

walks away
by One Six One February 06, 2008
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Not meaning “sister”. Commonly used to refer to a close friend or bestfriend.
what’s up, sis”
by kaitlyn pender January 24, 2019
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1) Short for sister
2) In the song Fuck the Pain Away by Peaches, SIS seems to stand for Stay In School...
My sis went to the movies with a scumball.

"Stay in school... Cause it's the best..."
by wxynot July 12, 2005
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