We found 30 dictionaries that define the word gamma rays:

General (13 matching dictionaries)

1. gamma rays: Merriam-Webster
2. gamma rays: Oxford Learner's Dictionaries
3. gamma rays: Collins English Dictionary
4. gamma rays: Vocabulary.com
5. gamma-rays, gamma rays: Wordnik
6. gamma rays: Cambridge Advanced Learner's Dictionary
7. gamma rays: Wiktionary
8. Gamma rays: Dictionary.com
9. Gamma rays: Wikipedia, the Free Encyclopedia
10. gamma rays: Stammtisch Beau Fleuve Acronyms
11. Gamma-rays, gamma rays: TheFreeDictionary.com

Computing (1 matching dictionary)

12. Gamma-rays, Gamma rays: Encyclopedia

Medicine (7 matching dictionaries)

13. gamma rays: Merriam-Webster Medical Dictionary
14. Dorland's Illustrated Medical Dictionary (No longer online)
15. online medical dictionary (No longer online)
16. Medical Device Glossary of Terms (No longer online)
17. Gamma-rays, Gamma rays: Medical dictionary
18. Hyperdictionary (No longer online)
19. Medical Dictionary (No longer online)

Science (3 matching dictionaries)

20. From Stargazers to Starships Glossary (No longer online)
21. General Chemistry Online (No longer online)
22. Accelerator Glossary (No longer online)

Slang (1 matching dictionary)

23. Gamma Rays: Urban Dictionary

Tech (5 matching dictionaries)

24. gamma rays: Electronics
25. Basics of Space Flight Glossary (No longer online)
26. Gamma rays: Gems and Precious Stones
27. SOLAR-TERRESTRIAL TERMS (No longer online)
28. Nuclear Terms (No longer online)

(Note: See gamma_ray as well.)

Definitions from Wiktionary (gamma ray) ▸ noun:  Very high frequency (and therefore very high energy) electromagnetic radiation emitted as a consequence of radioactivity. ▸ Also see gamma_ray Opposite: alphrays, betrays, X-rays Phrases: The Effect of Gamma Rays on Man-in-the-Moon Marigolds, more... ▸ Words similar to gamma rays ▸ Usage examples for gamma rays ▸ Idioms related to gamma rays ▸ Wikipedia articles (New!) ▸ Words that often appear near gamma rays ▸ Rhymes of gamma rays ▸ Invented words related to gamma rays