We found 14 dictionaries that define the word alpha rays:

General (9 matching dictionaries)

1. alpha rays: Collins English Dictionary
2. alpha rays: Vocabulary.com
3. alpha rays: Wordnik
4. alpha rays: Wiktionary
5. Alpha rays: Dictionary.com
6. Alpha rays: Wikipedia, the Free Encyclopedia
7. alpha rays: Stammtisch Beau Fleuve Acronyms
8. alpha rays: FreeDictionary.org
9. Alpha rays, alpha-rays: TheFreeDictionary.com

Computing (1 matching dictionary)

10. Alpha rays, alpha-rays: Encyclopedia

Medicine (3 matching dictionaries)

11. alpha rays: Merriam-Webster Medical Dictionary
12. Dorland's Illustrated Medical Dictionary (No longer online)
13. Alpha rays, alpha-rays: Medical dictionary

Tech (1 matching dictionary)

14. Alpha rays: Gems and Precious Stones

(Note: See alpha_ray as well.)

Definitions from Wiktionary (alpha ray) ▸ noun:  A stream of alpha particles. ▸ Also see alpha_ray Types: alphparticles, more... ▸ Words similar to alpha rays ▸ Usage examples for alpha rays ▸ Idioms related to alpha rays ▸ Wikipedia articles (New!) ▸ Words that often appear near alpha rays ▸ Rhymes of alpha rays ▸ Invented words related to alpha rays