We found 54 dictionaries that define the word photon:

General (22 matching dictionaries)

1. photon: Longman Dictionary of Contemporary English
2. photon: Merriam-Webster
3. photon: Oxford Learner's Dictionaries
4. photon: American Heritage Dictionary of the English Language
5. photon: Collins English Dictionary
6. photon: Vocabulary.com
7. Photon, photon: Wordnik
8. photon: Cambridge Advanced Learner's Dictionary
9. photon: Wiktionary
10. photon: Webster's New World College Dictionary, 4th Ed.
11. photon: The Wordsmyth English Dictionary-Thesaurus
12. photon: Infoplease Dictionary
13. photon: Dictionary.com
14. photon: Online Etymology Dictionary
15. Photon (Image Comics), Photon (TV series), Photon (album), Photon (anime), Photon (comics), Photon (disambiguation), Photon: Wikipedia, the Free Encyclopedia
16. photon: Rhymezone
17. photon: FreeDictionary.org
18. photon: The Phrontistery - A Dictionary of Obscure Words
19. photon: Mnemonic Dictionary
20. photon: TheFreeDictionary.com

Art (1 matching dictionary)

21. photon: ArtLex Lexicon of Visual Art Terminology

Business (1 matching dictionary)

22. photon: Legal dictionary

Computing (2 matching dictionaries)

23. photon: Encyclopedia
24. Windows API Guide (No longer online)

Medicine (4 matching dictionaries)

25. photon: Merriam-Webster Medical Dictionary
26. Dorland's Illustrated Medical Dictionary (No longer online)
27. online medical dictionary (No longer online)
28. photon: Medical dictionary

Miscellaneous (2 matching dictionaries)

29. PHOTON: Acronym Finder
30. AbbreviationZ (No longer online)

Science (11 matching dictionaries)

31. From Stargazers to Starships Glossary (No longer online)
32. Chemistry Dictionary (No longer online)
33. Photon: Eric Weisstein's World of Physics
34. Imagine the Universe! Dictionary (No longer online)
35. Photon: Extragalactic Astronomy
36. Photon: NRC Glossary of Nuclear Terms --
37. photon: UNCChem Glossary
38. Atmospheric Chemistry and Air Quality (No longer online)
39. Accelerator Glossary (No longer online)
40. How Many? A Dictionary of Units of Measurement (No longer online)
41. PHOTON: Zoom Astronomy Glossary

Slang (1 matching dictionary)

42. Photon: Urban Dictionary

Tech (10 matching dictionaries)

43. photon: Webster's New World Telecom Dictionary
44. High-Energy Astrophysics (No longer online)
45. photon: Electronics
46. photon: Glossary of Related Solar Power Terms
47. AUTOMOTIVE TERMS (No longer online)
48. photon: Solar Electric Glossary
49. Glossary of Meteorology (No longer online)
50. Explosives (No longer online)
51. JPL Terms (No longer online)
52. Glossary of Energy Terms (No longer online)

(Note: See photonic as well.)

Definitions from Wiktionary ( ) ▸ noun:  (physics) The quantum of light and other electromagnetic energy, regarded as a discrete particle having zero rest mass, no electric charge, and an indefinitely long lifetime. It is a gauge boson. Similar: proto-photon, superphoton, monophoton, super-photon, soft photon, phonon, photonics, antiphoton, photino, luxon, more... Opposite: antiparticle Types: gamma ray, X-ray, ultraviolet, visible light, infrared, microwave, radio wave, more... Phrases: photon flux, incident photon, Photon counting, photon density, virtual photon, more... Adjectives: single, ray, scattered, virtual, two, absorbed, incoming, ieee, second, individual, original Colors:     blue,     violet,     indigo,     ultraviolet,     infrared, more... ▸ Word origin ▸ Words similar to photon ▸ Usage examples for photon ▸ Idioms related to photon ▸ Wikipedia articles (New!) ▸ Popular adjectives describing photon ▸ Words that often appear near photon ▸ Rhymes of photon ▸ Invented words related to photon