n. The dry, annoying piece of shit on the tip of a bottle of mustard.
Before you squirt that shit on your burger, be sure to pick off the crustard first, dude!
A pastry often mistaken for a pie, in which a single pie crust is filled with a homogenous egg-based filling.
"Mmm, I love pumpkin crustard!"
"Don't you mean pumpkin pie?"
"No, this is a crustard. Note how it's pretty much just a custard in a single crust."