Definition of pileup
1 : a collision involving usually several motor vehicles
2a : a jammed tangled mass or pile (as of motor vehicles or people) resulting from collision or accumulationb : accumulation
Examples of pileup in a sentence
A five-car pileup slowed traffic.
a pileup of e-mail messages that needed to be dealt with
First Known Use of pileup
PILEUP Defined for English Language Learners
Definition of pileup for English Language Learners
: an accident in which several or many vehicles crash into each other
: a large amount of something that has increased gradually over a period of time
Seen and Heard
What made you want to look up pileup? Please tell us where you read or heard it (including the quote, if possible).