We found 33 dictionaries that define the word onto:

General (22 matching dictionaries)

1. onto, onto-: Merriam-Webster.com
2. onto: Oxford Learner's Dictionaries
3. onto, onto-: American Heritage Dictionary of the English Language
4. onto, onto-: Collins English Dictionary
5. Onto, onto: Wordnik
6. onto: Cambridge Advanced Learner's Dictionary
7. onto, onto-: Wiktionary
8. onto, onto-: Webster's New World College Dictionary, 4th Ed.
9. onto, onto (ont-): The Wordsmyth English Dictionary-Thesaurus
10. onto: Infoplease Dictionary
11. Onto, onto, onto-: Dictionary.com
12. onto: Online Etymology Dictionary
13. onto: Cambridge Essential American English Dictionary
14. Onto: Wikipedia, the Free Encyclopedia
15. Onto: Online Plain Text English Dictionary
16. onto: Webster's Revised Unabridged, 1913 Edition
17. Onto: AllWords.com Multi-Lingual Dictionary
18. ONTO: Dictionary of Americanisms (1848)
19. onto: Free Dictionary
20. onto, onto-: Dictionary/thesaurus

Art (1 matching dictionary)

21. onto-: A Cross Reference of Latin and Greek Elements

Computing (2 matching dictionaries)

22. onto: Free On-line Dictionary of Computing
23. onto: Encyclopedia

Medicine (2 matching dictionaries)

24. online medical dictionary (No longer online)
25. onto-: Medical dictionary

Miscellaneous (2 matching dictionaries)

26. AbbreviationZ (No longer online)
27. onto: Idioms

Science (2 matching dictionaries)

28. Onto: Eric Weisstein's World of Mathematics
29. onto: PlanetMath Encyclopedia

Slang (2 matching dictionaries)

30. onto: Green’s Dictionary of Slang
31. onto: Urban Dictionary

Definitions from Wiktionary ( ) ▸ adjective:  (mathematics, of a function) Assuming each of the values in its codomain; having its range equal to its codomain. Similar: INTO, down, across, back, through, towards, directly, From, accross, underneath, more... Opposite: off, away, from, from, out, of, detached Types: one-to-one, surjective, injective, bijective, more... Phrases: back onto, hold onto, hang onto, opened onto, get onto, more... ▸ Word origin ▸ Words similar to onto ▸ Usage examples for onto ▸ Idioms related to onto ▸ Wikipedia articles (New!) ▸ Popular nouns described by onto ▸ Words that often appear near onto ▸ Rhymes of onto ▸ Invented words related to onto