We found 51 dictionaries that define the word calcium:

General (27 matching dictionaries)

1. calcium: Merriam-Webster
2. calcium: Oxford Learner's Dictionaries
3. calcium: American Heritage Dictionary of the English Language
4. calcium: Collins English Dictionary
5. calcium: Vocabulary.com
6. Calcium, calcium: Wordnik
7. calcium: Cambridge Advanced Learner's Dictionary
8. calcium: Wiktionary
9. calcium: The Wordsmyth English Dictionary-Thesaurus
10. calcium: Infoplease Dictionary
11. calcium: Dictionary.com
12. calcium: Online Etymology Dictionary
13. calcium: Cambridge Essential American English Dictionary
14. Calcium (biology), Calcium (disambiguation), Calcium: Wikipedia, the Free Encyclopedia
15. Calcium: Online Plain Text English Dictionary
16. calcium: Webster's Revised Unabridged, 1913 Edition
17. calcium: Rhymezone
18. calcium, calcium (het), calcium (m): AllWords.com Multi-Lingual Dictionary
19. calcium: Webster's 1828 Dictionary
20. calcium: FreeDictionary.org
21. calcium: TheFreeDictionary.com
22. calcium: Wikimedia Commons US English Pronunciations
23. calcium: Webster's New World College Dictionary, 4th Ed.
24. calcium: Mnemonic Dictionary
25. calcium: Longman Dictionary of Contemporary English

Business (1 matching dictionary)

26. calcium: Financial dictionary

Computing (1 matching dictionary)

27. calcium: Encyclopedia

Medicine (15 matching dictionaries)

28. calcium: Merriam-Webster Medical Dictionary
29. Dorland's Illustrated Medical Dictionary (No longer online)
30. Calcium: MedTerms.com Medical Dictionary
31. Medical Dictionary (No longer online)
32. Calcium: Merck Manuals
33. online medical dictionary (No longer online)
34. Hepatitis C Information Central (No longer online)
35. Kidney Patient Guide Glossary (No longer online)
36. calcium: Dictionary of Cancer Terms
37. calcium: Parents' Common Sense Encyclopedia
38. Glossary of HIV/AIDS Related Terms (No longer online)
39. calcium: Medical dictionary
40. Calcium: Drug Medical Dictionary
41. Hyperdictionary (No longer online)
42. Calcium: Glossary of Herbs, Botanicals and Other Products

Science (3 matching dictionaries)

43. Environmental Terminology Discovery Service (No longer online)
44. Calcium: Extragalactic Astronomy
45. Calcium, calcium: WebElements Periodic Table of the Elements

Slang (1 matching dictionary)

46. Calcium: Urban Dictionary

Sports (1 matching dictionary)

47. Calcium: Body Building

Tech (2 matching dictionaries)

48. Explosives (No longer online)
49. Lake and Water Word Glossary (No longer online)

(Note: See calciums as well.)

Definitions from Wiktionary ( ) ▸ noun:  The chemical element (Symbol Ca), with an atomic number 20. It is a soft, silvery-white alkaline earth metal which occurs naturally as carbonate in limestone and as silicate in many rocks. ▸ noun:  (countable) An atom of this element. Similar: CA, atomic number 20, magnesium, potassium, tricalcium, dicalcium, sodium, calciferol, metasilicate, phosphate, more... Opposite: sodium, potassium, magnesium, phosphorus, chlorine Types: calcium carbonate, calcium citrate, calcium phosphate, calcium gluconate, calcium lactate, more... Phrases: calcium carbonate, Calcium channel, calcium chloride, serum calcium, calcium phosphate, more... Adjectives: intracellular, dietary, total, free, low, extracellular, urinary, more, high, cytosolic, enough Colors:     white,     light gray,     pale blue,     soft green,     cream, more... ▸ Word origin ▸ Words similar to calcium ▸ Usage examples for calcium ▸ Idioms related to calcium ▸ Wikipedia articles (New!) ▸ Popular adjectives describing calcium ▸ Words that often appear near calcium ▸ Rhymes of calcium ▸ Invented words related to calcium