The white, bitter layer under the orange rind, that likes to cling to the flesh of the orange like fat to a steak. Also known as the pericarp.
Guy 1, "Dude! What are you doing to that orange?"
Guy 2, "I'm trying to scrape all the orange fat off."
Guy 1. "Dude, just eat it."
Guy 2, "I can't. It scares me..."