We found 22 dictionaries that define the word ions:

General (10 matching dictionaries)

1. -ions, ions: Merriam-Webster
2. ions: Collins English Dictionary
3. ions: Vocabulary.com
4. Ion's, Ions, ion's, ions: Wordnik
5. ions: Cambridge Advanced Learner's Dictionary
6. Ions, ions: Wiktionary
7. ions: Dictionary.com
8. ions: Cambridge Essential American English Dictionary
9. IONS, Ions: Wikipedia, the Free Encyclopedia
10. Ions: TheFreeDictionary.com

Computing (1 matching dictionary)

11. Ions: Encyclopedia

Medicine (7 matching dictionaries)

12. ions: Merriam-Webster Medical Dictionary
13. Medical Dictionary (No longer online)
14. online medical dictionary (No longer online)
15. DICTIONARY OF TERMS IN ORAL PHYSIOLOGY (No longer online)
16. Ions: MEDLINE plus Illustrated Medical Encyclopedia
17. Ions: Medical dictionary
18. University of Maryland Glossary of Medical Terms (No longer online)

Miscellaneous (2 matching dictionaries)

19. IONS: Acronym Finder
20. AbbreviationZ (No longer online)

Science (1 matching dictionary)

21. Imagine the Universe! Dictionary (No longer online)

Tech (1 matching dictionary)

22. High-Energy Astrophysics (No longer online)

(Note: See ion as well.)

Definitions from Wiktionary (Ions) ▸ noun:  A surname originating as a patronymic. Similar: anion, cation, ionization, ionise, electron, proton, ionics, hydronium, molecule, photoelectron, more... Opposite: atoms, neutrals, molecules, elements, compounds Types: positive, negative, anionic, cations, anions, more... Phrases: hydrogen ions, positive ions, calcium ions, negative ions, chloride ions, more... Adjectives: positive, negative, heavy, free, complex, molecular, metallic, inorganic, various, metal, ferric ▸ Words similar to ions ▸ Usage examples for ions ▸ Idioms related to ions ▸ Wikipedia articles (New!) ▸ Popular adjectives describing ions ▸ Words that often appear near ions ▸ Rhymes of ions ▸ Invented words related to ions