We found 20 dictionaries that define the word antiproton:

General (17 matching dictionaries)

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

Computing (1 matching dictionary)

18. antiproton: Encyclopedia

Science (1 matching dictionary)

19. Antiproton: Eric Weisstein's World of Physics

Tech (1 matching dictionary)

20. Glossary of Meteorology (No longer online)

(Note: See antiprotons as well.)

Definitions from Wiktionary (antiproton) ▸ noun:  (physics) The antiparticle of the proton, having a negative electric charge. Similar: antihydrogen, protonium, antiatom, antiprotonic helium, antiphoton, anti-particle, antipion, positron, antinucleon, antielement, more... Opposite: proton, particle, matter ▸ Words similar to antiproton ▸ Usage examples for antiproton ▸ Idioms related to antiproton ▸ Wikipedia articles (New!) ▸ Popular adjectives describing antiproton ▸ Words that often appear near antiproton ▸ Rhymes of antiproton ▸ Invented words related to antiproton