Definition of iodine
1 : a nonmetallic halogen element obtained usually as heavy shining blackish-gray crystals and used especially in medicine, photography, and analysis — see element table
2 : a tincture of iodine used especially as a topical antiseptic
Did You Know?
Iodine is a nonmetallic chemical element and the heaviest nonradioactive halogen. It is a very nearly black crystalline solid that can turn to a deep violet, irritating vapor. In nature it is never found uncombined, and occurs mostly in brines and seaweeds. Dietary iodine is essential for thyroid gland function, so table salt usually has potassium iodide added to prevent iodine deficiency. Elemental iodine is used in medicine, in synthesizing some organic chemicals, in manufacturing dyes, in analytical chemistry, and in photography. The radioactive isotope I-131, with an eight-day half-life, is very useful in medicine and other applications.
Origin and Etymology of iodine
French iode, from Greek ioeidēs violet colored, from ion violet
First Known Use: 1814
IODINE Defined for English Language Learners
Definition of iodine for English Language Learners
: a chemical element that is used especially in medicine and photography
IODINE Defined for Kids
Definition of iodine for Students
1 : a chemical element found in seawater and seaweeds and used especially in medicine and photography
2 : a solution of iodine in alcohol used to kill germs
Medical Definition of iodine
1: a nonmetallic halogen element obtained usually as heavy shining blackish gray crystals and used especially in medicine (as in antisepsis and in the treatment of goiter and cretinism) and in photography and chemical analysis—symbol I; see element table
2: a tincture of iodine used especially as a topical antiseptic
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