We found 12 dictionaries that define the word gillion:

General (7 matching dictionaries)

1. gillion: Collins English Dictionary
2. Gillion: Wordnik
3. gillion: Wiktionary
4. gillion: Dictionary.com
5. Gillion: Wikipedia, the Free Encyclopedia
6. Gillion: Rhymezone
7. gillion: TheFreeDictionary.com

Computing (2 matching dictionaries)

8. gillion: Free On-line Dictionary of Computing
9. gillion: Encyclopedia

Medicine (1 matching dictionary)

10. online medical dictionary (No longer online)

Science (1 matching dictionary)

11. How Many? A Dictionary of Units of Measurement (No longer online)

Slang (1 matching dictionary)

12. gillion: Urban Dictionary

Definitions from Wiktionary (gillion) ▸ noun:  (slang, hyperbolic) An unspecified large number (of). Similar: gagillion, gabillion, grillion, gadzillion, gajillion, googillion, gallon, gigalitre, gigaliter, kilogallon, more... ▸ Words similar to gillion ▸ Usage examples for gillion ▸ Idioms related to gillion ▸ Wikipedia articles (New!) ▸ Popular adjectives describing gillion ▸ Words that often appear near gillion ▸ Rhymes of gillion ▸ Invented words related to gillion