What is "ionian mode"

Ionic \I*on"ic\, a. [L. Ionicus, Gr. ?, fr. ? Ionia.]

1. Of or pertaining to Ionia or the Ionians.

2. (Arch.) Pertaining to the Ionic order of architecture, one of the three orders invented by the Greeks, and one of the five recognized by the Italian writers of the sixteenth century. Its distinguishing feature is a capital with spiral volutes. See Illust. of Capital.

   Ionic dialect (Gr. Gram.), a dialect of the Greek language, used in Ionia. The Homeric poems are written in what is designated old Ionic, as distinguished from new Ionic, or Attic, the dialect of all cultivated Greeks in the period of Athenian prosperity and glory.

   Ionic foot. (Pros.) See Ionic, n., 1.

   Ionic mode, or Ionian mode, (Mus.), an ancient mode, supposed to correspond with the modern major scale of C.

   Ionic sect, a sect of philosophers founded by Thales of Miletus, in Ionia. Their distinguishing tenet was, that water is the original principle of all things.

   Ionic type, a kind of heavy-faced type (as that of the following line).

   Note: This is Nonpareil Ionic.

Ionian mode is the name assigned by Heinrich Glarean in 1547 to his new authentic mode on C (mode 11 in his numbering scheme), which uses the diatonic octave species from C to the C an octave higher, divided at G (as its dominant, reciting note or tenor) into a fourth species of perfect fifth (tone–tone–semitone–tone) plus a third species of perfect fourth (tone–tone–semitone): C D E F G + G A B C . This octave species is essentially the same as the major mode of tonal music .

Church music had been explained by theorists as being organised in eight musical modes: the scales on D, E, F, and G in the "greater perfect system" of "musica recta" , each with their authentic and plagal counterparts.

Glarean's twelfth mode was the plagal version of the Ionian mode, called Hypoionian (under Ionian), based on the same relative scale, but with the major third as its tenor, and having a melodic range from a perfect fourth below the tonic, to a perfect fifth above it .