from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A lustrous, purple-black, corrosive, poisonous halogen occurring as a diatomic molecule, I2, that easily sublimes to give a purple gas and is a trace element essential for proper thyroid function. Radioactive isotopes, especially I-131, are used as medical tracers and in thyroid disease diagnosis and therapy. Iodine compounds are used as germicides, antiseptics, and dyes. Atomic number 53; atomic weight 126.9045; melting point 113.7°C; boiling point 184.4°C; density of gas 11.27 grams per liter; specific gravity (solid, at 20°C) 4.93; valence 1, 3, 5, 7. cross-reference: Periodic Table.
  • noun An antiseptic preparation containing iodine in solution, used to treat wounds.

from The Century Dictionary.

  • noun Chemical symbol, I; atomic weight, 126.9. In chem., a peculiar non-metallic elementary solid substance, forming one of the group of halogens.

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Chem.) A nonmetallic element, of the halogen group of atomic number 53, occurring always in combination, as in the iodides. When isolated it is in the form of dark gray metallic scales, resembling plumbago, soft but brittle, and emitting a chlorinelike odor. Symbol I. Atomic weight 126.90. If heated, iodine volatilizes in beautiful violet vapors.
  • noun an artificial green dyestuff, consisting of an iodine derivative of rosaniline; -- called also night green.
  • noun a pigment of an intense scarlet color, consisting of mercuric iodide.
  • noun a brilliant yellow pigment, consisting of plumbic iodide.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A chemical element (symbol: I) with an atomic number of 53; one of the halogens.
  • noun An antiseptic incorporating the element.
  • noun countable, uncountable, obsolete An iodide.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a nonmetallic element belonging to the halogens; used especially in medicine and photography and in dyes; occurs naturally only in combination in small quantities (as in sea water or rocks)
  • noun a tincture consisting of a solution of iodine in ethyl alcohol; applied topically to wounds as an antiseptic


from The American Heritage® Dictionary of the English Language, 4th Edition

[French iode, iodine (from Greek ioeidēs, violet-colored : ion, violet + -oeidēs, -oid) + –ine.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From French iode, from Ancient Greek ἰοειδής ("violet") + -ine



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  • I.

    December 16, 2007

  • "Iodine is used in chemistry as an indicator for starch. When starch is mixed with iodine in solution, an intensely dark blue colour develops, representing a starch/iodine complex. Starch is a substance common to most plant cells and so a weak iodine solution will stain starch present in the cells. Iodine is one component in the staining technique known as Gram staining, used in microbiology. Lugol's solution or Lugol's iodine (IKI) is a brown solution that turns black in the presence of starches and can be used as a cell stain, making the cell nuclei more visible. Iodine is also used as a mordant in Gram's staining, it enhances dye to enter through the pore present in the cell wall/membrane."


    May 9, 2017