1. n - the usually foul-tasting mucus substance which drips down the back of one's throat following nasal administration, usually of illicit drugs.
'Outta my way, this backdrop is so rancid I think I'm gonna puke'
by abo nick September 28, 2006
A high that one can obtain a few days after he's smoked pot
"Gabriel had a backdrop in spanish class today. He was laughing like a douche"
by Frankenmanwolfenstein February 12, 2008