Sis 

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

Sis by Theworldisflat.edu August 3, 2018

sis 

Short for sister, commonly used as a term of endearment to friends in urban new york/jersey areas

hey, sis, whats up

sis by Caroline Might Fine November 14, 2016

sis 

Not meaning “sister”. Commonly used to refer to a close friend or bestfriend.

“what’s up, sis”

sis by kaitlyn pender January 24, 2019

SiS 

Suffering in Silence

Im alone now.. SiS.

SiS by wockh☆rdt January 3, 2023

sis 

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..."

sis by wxynot July 31, 2005

sis 

Slang for sister

Me and my sis went to the movies.

sis by Thunderchild March 25, 2003

SIS 

Abbreviation for: "Sisters, In, Spirit". Your Best Friend or Bae. Usually used to refer to someone really close to you, someone you spend a lot of time with, like your sister.

Girl: OMG, squad on fleek!
Girl 2: yas, we look #Fabulous
Girl: Yas Sis Yas!

SIS by ChocolateWafflez April 15, 2015