We found 20 dictionaries that define the word cosmic rays:

General (10 matching dictionaries)

1. cosmic rays: Merriam-Webster
2. cosmic rays: Collins English Dictionary
3. cosmic rays: Vocabulary.com
4. cosmic rays: Wiktionary
5. cosmic rays: The Wordsmyth English Dictionary-Thesaurus
6. cosmic rays: Dictionary.com
7. Cosmic rays: Wikipedia, the Free Encyclopedia
8. cosmic rays: TheFreeDictionary.com

Computing (2 matching dictionaries)

9. cosmic rays: Free On-line Dictionary of Computing
10. cosmic rays: Encyclopedia

Medicine (2 matching dictionaries)

11. online medical dictionary (No longer online)
12. cosmic rays: Medical dictionary

Science (2 matching dictionaries)

13. Cosmic Rays: Eric Weisstein's World of Physics
14. Imagine the Universe! Dictionary (No longer online)

Slang (1 matching dictionary)

15. Cosmic Rays: Urban Dictionary

Tech (3 matching dictionaries)

16. High-Energy Astrophysics (No longer online)
17. Glossary of Meteorology (No longer online)
18. Explosives (No longer online)

(Note: See cosmic_ray as well.)

Definitions from Wiktionary (cosmic ray) ▸ noun:  (astronomy) An energetic particle originating outside our solar system. ▸ noun:  (astronomy) Cosmic radiation: a stream of cosmic rays. ▸ Also see cosmic_ray Opposite: terrestrial rays, solar radiation Types: alphrays, betrays, gammrays, x-rays, more... Phrases: Health threat from cosmic rays, more... ▸ Words similar to cosmic rays ▸ Usage examples for cosmic rays ▸ Idioms related to cosmic rays ▸ Wikipedia articles (New!) ▸ Words that often appear near cosmic rays ▸ Rhymes of cosmic rays ▸ Invented words related to cosmic rays