We found 33 dictionaries that define the word either:

General (28 matching dictionaries)

1. either: Merriam-Webster
2. either: Oxford Learner's Dictionaries
3. either: American Heritage Dictionary of the English Language
4. either: Collins English Dictionary
5. either: Vocabulary.com
6. Either, either: Wordnik
7. either: Cambridge Advanced Learner's Dictionary
8. either: Wiktionary
9. either: Webster's New World College Dictionary, 4th Ed.
10. either: The Wordsmyth English Dictionary-Thesaurus
11. either: Infoplease Dictionary
12. Either, either: Dictionary.com
13. either: Online Etymology Dictionary
14. either: Cambridge Essential American English Dictionary
15. Either: Wikipedia, the Free Encyclopedia
16. Either: Online Plain Text English Dictionary
17. either: Webster's Revised Unabridged, 1913 Edition
18. either: Rhymezone
19. either: AllWords.com Multi-Lingual Dictionary
20. either: Webster's 1828 Dictionary
21. Either: Dictionary of Phrase and Fable (1898)
22. either: FreeDictionary.org
23. either: Mnemonic Dictionary
24. either: TheFreeDictionary.com
25. either: Wikimedia Commons US English Pronunciations
26. either: Longman Dictionary of Contemporary English

Business (1 matching dictionary)

27. either: Legal dictionary

Medicine (1 matching dictionary)

28. online medical dictionary (No longer online)

Miscellaneous (2 matching dictionaries)

29. Navajo Code Talkers' Dictionary (No longer online)
30. either: Idioms

Slang (1 matching dictionary)

31. either: Urban Dictionary

(Note: See eithers as well.)

Definitions from Wiktionary ( ) ▸ adverb:  (conjunctive, after a negative) As well. Similar: unless, otherwise, even, directly, necessarily, anything, entirely, possibly, neither, Both, more... Opposite: neither, none, nor, never, excluding Types: neither, both, all, none, more... Phrases: either way, either or, either or order, either way market, either or facility, more... Adjectives: certain, other, unfit, pallid, bound, binary, digit, fallopian, chronic, decent, live Colors:     black,     white,     gray,     red,     blue, more... ▸ Word origin ▸ Words similar to either ▸ Usage examples for either ▸ Idioms related to either ▸ Wikipedia articles (New!) ▸ Words that often appear near either ▸ Rhymes of either ▸ Invented words related to either