Io ['ī-(,)ō] -n

  1. a maiden loved by Zeus and changed by him into a heifer so that she might escape the jealous rage of Hera

IOC -abbr

  1. International Olympic Committee

iod- -comb form

  1. iodine
    • iod ize
    • iodo form

io·date ['ī-ə-,dāt, -dət] -n

  1. a salt containing the IO 3 ion

io·dide ['ī-ə-,dīd] -n

  1. a salt of hydriodic acid
  2. the monovalent anion I of such a salt

io·din·ate ['ī-ə-də-,nāt] -vt, n

  1. to treat or cause to combine with iodine or a compound of iodine

io·dine ['ī-ə-,dīn, -dᵊn, -,dēn] -n

  1. a nonmetallic halogen element obtained usu. as heavy shining blackish-gray crystals and used esp. in medicine, photography, and analysis
  2. a tincture of iodine used esp. as a topical antiseptic

io·dise ['ī-ə-,dīz] -vt

(variant of iodize)

  1. to treat with iodine or an iodide
    • iodized salt

io·dize ['ī-ə-,dīz] -vt

  1. to treat with iodine or an iodide
    • iodized salt

io·do·form [ī-'ō-də-,fȯrm, -'ä-] -n

  1. a yellow crystalline volatile compound CHI 3with a penetrating persistent odor that is used as an antiseptic dressing

io·do·phor [-,fȯr] -n

  1. a complex of iodine and a surface-active agent that releases iodine gradually and serves as a disinfectant

io·dop·sin [,ī-ə-'däp-sən] -n

  1. a photosensitive violet pigment in the retinal cones that is similar to rhodopsin but more labile, is formed from vitamin A, and is important in daylight vision

IOM -abbr

  1. Isle of Man

Io moth ['ī-(,)ō-] -n

  1. a chiefly No. American saturniid moth ( Automeris io) having a large circular eyelike spot on the upper surface of each hind wing and a green larva with stinging spines

ion ['ī-ən, 'ī-,än] -n

  1. an atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons
  2. a charged subatomic particle (as a free electron)

Ion -abbr

  1. Ionic

ion channel -n

  1. a cell membrane channel that is selectively permeable to certain ions (as of calcium or sodium)

ion engine -n

  1. a reaction engine deriving thrust from the ejection of a stream of ionized particles

ion exchange -n

  1. a reversible interchange of one kind of ion present on an insoluble solid with another of like charge present in a solution surrounding the solid with the reaction being used esp. for softening or demineralizing water, the purification of chemicals, or the separation of substances

ion exchange resin -n

  1. an insoluble material of high molecular weight that contains groups which can be exchanged with ions in a solution with which it is in contact

Io·ni·an [ī-'ō-nē-ən] -n, adj

  1. a member of any of the Greek peoples who settled on the islands of the Aegean Sea and the western shore of Asia Minor toward the end of the second millennium b.c.
  2. a native or inhabitant of Ionia

ion·ic [ī-'ä-nik] -adj, n

  1. of, relating to, existing as, or characterized by ions
    • ionic gases
    • the ionic charge
  2. based on or functioning by means of ions
    • ionic conduction

Ion·ic [ī-'ä-nik] -adj

  1. of or relating to the ancient Greek architectural order distinguished esp. by fluted columns on bases and scroll volutes in its capitals
  2. of or relating to Ionia or the Ionians

Ionic -n

  1. a dialect of ancient Greek spoken esp. in Ionia and the Cyclades

ionic bond -n

  1. a chemical bond formed between oppositely charged species because of their mutual electrostatic attraction

ion·ise ['ī-ə-,nīz] -vb, adj, n

(variant of ionize)

  1. to convert wholly or partly into ions
  2. to become ionized

io·ni·um [ī-'ō-nē-əm] -n

  1. a natural radioactive isotope of thorium having a mass number of 230

ionization chamber -n

  1. a partially evacuated tube provided with electrodes so that its conductivity due to the ionization of the residual gas reveals the presence of ionizing radiation

ion·ize ['ī-ə-,nīz] -vb, adj, n

  1. to convert wholly or partly into ions
  2. to become ionized

ion·o·phore [ī-'ä-nə-,fȯr] -n

  1. a compound that facilitates transmission of an ion (as of calcium) across a lipid barrier (as in a cell membrane) by combining with the ion or by increasing the permeability of the barrier to it

ion·o·sphere [ī-'ä-nə-,sfir] -n, adj, adv

  1. the part of the earth's atmosphere in which ionization of atmospheric gases affects the propagation of radio waves, which extends from about 30 miles (50 kilometers) to the exosphere, and which is contiguous with the upper portion of the mesosphere and the thermosphere
  2. a comparable region of charged particles surrounding another celestial body (as Venus)

ion·to·pho·re·sis [(,)ī-,än-tə-fə-'rē-səs] -n, adj, adv

  1. the introduction of an ionized substance (as a drug) through intact skin by the application of a direct electric current

IOOF -abbr

  1. Independent Order of Odd Fellows

io·ta [ī-'ō-tə] -n

  1. the 9th letter of the Greek alphabet
  2. an infinitesimal amount : jot
    • did not show an iota of interest

IOU [,ī-(,)ō-'yü] -n

  1. a paper that has on it the letters IOU, a stated sum, and a signature and that is given as an acknowledgment of debt
  2. debt, obligation

IOW -abbr

  1. Isle of Wight