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3. SIU
Acronym for Special Investigation Unit for law enforcement/prosecutors and insurance compaines
When that boatload of coal claimed whiplash, they called SIU in to videotape them playing basketball
1. SIU
SIU = Southern Illinois University, located in Carbondale, Illinois. Home of the Salukis!
SIU basketball dominates the Missouri Valley.

SIU is one of the top party schools in the nation.
2. SIU
An acronym for "suck it up"
Person 1: Ow, I bumped into that wall.
Person 2: Man, SIU go beast it
4. SIU
Acronym for 'step it up' meaning for one to reach a new/higher level then previously on.

Commonly used in forums and online gaming.
Guy 1: Dude, your bottom of the team. SIU

Guy 2: Hey, I'm new, I'm trying my best okay!
5. Siu
a unit of measurement equalling 5'0"
Slocum Hall's rotunda is about 3 sius tall.
by Brandice Feb 25, 2003 add a video
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