We found 23 dictionaries that define the word quintillion:

General (17 matching dictionaries)

1. quintillion: Merriam-Webster
2. quintillion: Oxford Learner's Dictionaries
3. quintillion: American Heritage Dictionary of the English Language
4. quintillion: Collins English Dictionary
5. quintillion: Vocabulary.com
6. quintillion: Wordnik
7. quintillion: Wiktionary
8. quintillion: Webster's New World College Dictionary, 4th Ed.
9. quintillion: The Wordsmyth English Dictionary-Thesaurus
10. quintillion: Infoplease Dictionary
11. quintillion: Dictionary.com
12. quintillion: Online Etymology Dictionary
13. Quintillion: Wikipedia, the Free Encyclopedia
14. quintillion: Rhymezone
15. quintillion: FreeDictionary.org
16. quintillion: Mnemonic Dictionary
17. quintillion: TheFreeDictionary.com

Computing (3 matching dictionaries)

18. quintillion: Free On-line Dictionary of Computing
19. quintillion: CCI Computer
20. quintillion: Encyclopedia

Medicine (1 matching dictionary)

21. online medical dictionary (No longer online)

Science (1 matching dictionary)

22. Quintillion: Eric Weisstein's World of Mathematics

Slang (1 matching dictionary)

23. quintillion: Urban Dictionary

(Note: See quintillions as well.)

Definitions from Wiktionary (quintillion) ▸ noun:  (figuratively, slang, hyperbolic) Any very large number, exceeding normal description. Similar: quadrillion, umptillion, quintillionaire, squillion, nonillion, infinitillion, jillion, zillion, scrillion, jazillion, more... Opposite: quadrillion, sextillion, septillion ▸ Word origin ▸ Words similar to quintillion ▸ Usage examples for quintillion ▸ Idioms related to quintillion ▸ Wikipedia articles (New!) ▸ Popular adjectives describing quintillion ▸ Words that often appear near quintillion ▸ Rhymes of quintillion ▸ Invented words related to quintillion