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1.
A type of facial hair which is formed when two sideburns on one's face do not have ending points, but rather connect at the chin area, forming a continuous 'burn along the jawline.
Dude, check out Colin's uniburn! It's so BAMF!!
by Ethannnn September 05, 2007
 
2.
is when you grow out your chops down around your chin/neck area and then shave off your bangs and the back of your head so that you have one continuous burn all the way around your face.
Duder, did you see that guys uniburn. It was bad arse

Dude, does that girl, Keri, hvae a uniburn?

Yeah Dude, it was nut sack.
by grant sweeting March 17, 2006
 
3.
Facial hair in which the sideburns extend across the upper lip and connect as a mustache. Distinguished from muttonchops by the absence of significant widening.

Derived from unibrow.
My friend sported a bizarre uniburn in celebration of Mustache Alive 2005.
by Janet February 14, 2005