a "pile up" is when u take a monster shit, and when da shit gets piled up on da otha shit.
omg man, afta i ate dat spicy ass taco bell, i had such a big ass pile up it was starting 2 overflow in da toilet.
by pimp daddy dollars September 06, 2004
A once-common game played mainly by boys in their first year of secondary school at Inverkeithing High School in Fife, Scotland. When on a crowded double-decker bus, one must stand at the bottom of the stairs between the two decks and not move. Others will stand behind you, and as many people will try to cram themselves into that tiny little space as possible. Some will get a bit too excited, attacking people and jumping off the top deck, inevitably leading to a riot.
"I heard Chris and John got into trouble yesterday by playing Pile-Up."
by SmileyDudette July 08, 2009
a collision involving numerous motor vehicles
There is a nasty pileup on the highway.
by The Return of Light Joker November 05, 2008