(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.
I was balls deep in her thighcaps lastnight and totally donkey punched her for the money shot!
"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."