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1.
Bring Your Own Liquor.
"PARTY TONIGHT, BYOL."
by ohemgrace July 26, 2009
 
2.
Acronym for "Bring Your Own Lube"

This might be specified if one was inviting peeps to a swing party where personal lube would be used for sexual purposes
BYOL if you are into Greek sex.
by Hoosier Jake July 05, 2010
 
3.
Bring your own legs
Dude this party is BYOL
by awyeanigs April 24, 2013