(noun)Synonym for the human buttocks. Created by Rainn Wilson from "The Office" on an interview on the Preston and Steve Show (93.3 WMMR, Philadelphia) on 16 July 2008.
"Just went to the gym and was at a treadmill next to this thighranosaurus rex"
"The hell's a thighranosaurus?"
"Bitch had bars of iron for legs and could probably reach the top shelf at Costco by jumping."