We found 21 dictionaries that define the word pile up:

General (15 matching dictionaries)

1. pile up: Longman Dictionary of Contemporary English
2. pile up: Oxford Learner's Dictionaries
3. pile-up, pile-up, pile up: Collins English Dictionary
4. pile up: Vocabulary.com
5. Pile-Up, pile-up: Wordnik
6. pile-up, pile (sth) up, pile up: Cambridge Advanced Learner's Dictionary
7. pile-up, pile up: Wiktionary
8. pile-up, pile up: Dictionary.com
9. Pile-up: Wikipedia, the Free Encyclopedia
10. pile up: Rhymezone
11. pile up: FreeDictionary.org
12. pile up: Mnemonic Dictionary
13. pile-up, pile up: TheFreeDictionary.com

Business (1 matching dictionary)

14. pile up: Legal dictionary

Computing (1 matching dictionary)

15. pile up: Encyclopedia

Medicine (1 matching dictionary)

16. pile up: Medical dictionary

Miscellaneous (1 matching dictionary)

17. pile up: Idioms

Slang (1 matching dictionary)

18. pile-up, pile up: Urban Dictionary

Tech (1 matching dictionary)

19. Book Binding (No longer online)

(Note: See pile_ups as well.)

Definitions from Wiktionary (pile up) ▸ verb:  (transitive) To form a pile, stack, or heap. ▸ verb:  (idiomatic, intransitive) To collect or accumulate, as a backlog. Similar: stack up, heap up, hoard, gather, collect, amass, compile, accumulate, cumulate, conglomerate, more... Opposite: scatter, disperse, spread out, distribute Types: car pile up, traffic jam, congestion, more... Phrases: pile up clothes, more... Adjectives: traverse, draft, breakthrough, bumper to bumper, piledriving, stonewall, trip, nose to tail, standoff, torquey, banked ▸ Words similar to pile up ▸ Usage examples for pile up ▸ Idioms related to pile up ▸ Wikipedia articles (New!) ▸ Words that often appear near pile up ▸ Rhymes of pile up ▸ Invented words related to pile up