We found 42 dictionaries that define the word radioactive:

General (24 matching dictionaries)

1. radioactive: Longman Dictionary of Contemporary English
2. radioactive: Merriam-Webster
3. radioactive: Oxford Learner's Dictionaries
4. radioactive: American Heritage Dictionary of the English Language
5. radioactive: Collins English Dictionary
6. radioactive: Vocabulary.com
7. Radioactive, radioactive: Wordnik
8. radioactive: Cambridge Advanced Learner's Dictionary
9. radioactive: Wiktionary
10. radioactive: Webster's New World College Dictionary, 4th Ed.
11. radioactive: The Wordsmyth English Dictionary-Thesaurus
12. radioactive: Infoplease Dictionary
13. radioactive: Dictionary.com
14. radioactive: Online Etymology Dictionary
15. radioactive: Cambridge Essential American English Dictionary
16. Radioactive (Gene Simmons song), Radioactive (Imagine Dragons song), Radioactive (Kings of Leon song), Radioactive (Rita Ora song), Radioactive (The Firm song), Radioactive (Yelawolf album), Radioactive (disambiguation), Radioactive (film), Radioactive: Wikipedia, the Free Encyclopedia
17. radioactive: Rhymezone
18. radioactive: AllWords.com Multi-Lingual Dictionary
19. radioactive: FreeDictionary.org
20. radioactive: The Phrontistery - A Dictionary of Obscure Words
21. radioactive: Mnemonic Dictionary
22. radioactive: TheFreeDictionary.com

Business (1 matching dictionary)

23. BusinessDictionary.com (No longer online)

Computing (1 matching dictionary)

24. radioactive: Encyclopedia

Medicine (10 matching dictionaries)

25. radioactive: Merriam-Webster Medical Dictionary
26. Dorland's Illustrated Medical Dictionary (No longer online)
27. Radioactive: MedTerms.com Medical Dictionary
28. Breast Cancer Talking Dictionary (No longer online)
29. online medical dictionary (No longer online)
30. radioactive: Prostate Cancer Interactive Glossary
31. radioactive: Dictionary of Cancer Terms
32. radioactive: Medical dictionary
33. Radioactive: Drug Medical Dictionary
34. Hyperdictionary (No longer online)

Science (4 matching dictionaries)

35. Misunderstood Physics Terms (No longer online)
36. Radioactive: Eric Weisstein's World of Physics
37. Radioactive: Physic and Astronomy Glossary
38. radioactive: UNCChem Glossary

Slang (1 matching dictionary)

39. radioactive: Urban Dictionary

Tech (1 matching dictionary)

40. Radioactive: Gems and Precious Stones

(Note: See radioactively as well.)

Definitions from Wiktionary ( ) ▸ adjective:  Exhibiting radioactivity. ▸ adjective:  (figurative, rare) Dangerous and disgusting, particularly of people or ideas. ▸ noun:  Any radioactive substance. Similar: hot, irradiative, radioresistant, radiotransparent, radiable, radiationproof, photoresistant, shiny, reactable, weapons-grade, more... Opposite: stable, inert, nonradioactive, dormant, passive Types: alpha, beta, gamma, x-ray, neutron, more... Phrases: radioactive waste, radioactive decay, radioactive materials, radioactive isotopes, radioactive material, more... Adjectives: more, highly, non, less, weakly, very, level, toxic, various, longer, natural Colors:     neon green,     lime green,     electric yellow,     bright yellow,     chartreuse, more... ▸ Word origin ▸ Words similar to radioactive ▸ Usage examples for radioactive ▸ Idioms related to radioactive ▸ Wikipedia articles (New!) ▸ Popular adjectives describing radioactive ▸ Popular nouns described by radioactive ▸ Words that often appear near radioactive ▸ Rhymes of radioactive ▸ Invented words related to radioactive