We found 14 dictionaries that define the word roentgen rays:

General (7 matching dictionaries)

1. roentgen rays: Merriam-Webster
2. roentgen rays: Oxford Learner's Dictionaries
3. roentgen rays: Collins English Dictionary
4. Roentgen-rays: Wiktionary
5. Roentgen Rays: Wikipedia, the Free Encyclopedia
6. roentgen rays: FreeDictionary.org
7. Roentgen Rays: TheFreeDictionary.com

Art (1 matching dictionary)

8. roentgen rays: ArtLex Lexicon of Visual Art Terminology

Computing (1 matching dictionary)

9. roentgen rays: Encyclopedia

Medicine (3 matching dictionaries)

10. roentgen rays: Merriam-Webster Medical Dictionary
11. Dorland's Illustrated Medical Dictionary (No longer online)
12. Roentgen Rays: Medical dictionary

Tech (2 matching dictionaries)

13. Metal Terminology (No longer online)
14. Farrier & Hoofcare (No longer online)

(Note: See roentgen_ray as well.)

Definitions from WordNet (Roentgen ray) ▸ noun:  electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target ▸ Also see roentgen_ray ▸ Words similar to roentgen rays ▸ Usage examples for roentgen rays ▸ Idioms related to roentgen rays ▸ Wikipedia articles (New!) ▸ Words that often appear near roentgen rays ▸ Rhymes of roentgen rays ▸ Invented words related to roentgen rays