(ī·on′ik) adjective Chem.
1. Of, pertaining to, or containing ions.
2. Designating the theory of electrolytic dissociation, according to which the molecules of all acids, bases, and salts dissociate in varying degrees when they are dissolved in water and certain other solvents.

(ī·on′ik) adjective
1. Ionian.
2. Archit. Of or pertaining to an order of Greek architecture characterized by scroll–like ornaments of the capital. See illustration under CAPITAL.
3. In prosody, designating a metrical foot, consisting either of two long and two short syllables (– – ̆ ̆) and called greater Ionic, or Ionic a majore, or of two short and two long (̆ ̆ – –), when it is called lesser Ionic or Ionic a minore.
—noun
1. In prosody, an Ionic foot; also, a verse composed of Ionic feet.
2. A dialect of ancient Greek spoken in Ionia and in most of the Aegean Islands, divided into Old Ionic or Epic, the language of the Homeric poems, and New Ionic, of the fifth century B.C., used by Herodotus and Hippoccrates.
3. Printing A style of type with a large, heavy roman face. [<L Ionicus <Gk. Iōnikos]