Gregorian mode in the context of "Gregorian chant"

In chant, a reciting tone (also called a recitation tone) can refer to either a repeated musical pitch or to the entire melodic formula for which that pitch is a structural note. In Gregorian chant, the first is also called tenor, dominant or tuba, while the second includes psalm tones (each with its own associated Gregorian mode) as well as simpler formulae for other readings and for prayers.

In music theory, the term mode or modus is used in a number of distinct senses, depending on context.

Its most common use may be described as a type of musical scale coupled with a set of characteristic melodic and harmonic behaviors. It is applied to major and minor keys as well as the seven diatonic modes (including the former as Ionian and Aeolian) which are defined by their starting note or tonic. (Olivier Messiaen's modes of limited transposition are strictly a scale type.) Related to the diatonic modes are the eight church modes or Gregorian modes, in which authentic and plagal forms of scales are distinguished by ambitus and tenor or reciting tone. Although both diatonic and Gregorian modes borrow terminology from ancient Greece, the Greek tonoi do not otherwise resemble their medieval/modern counterparts.

The Ionian mode is a musical mode or, in modern usage, a diatonic scale also called the major scale. It is named after the Ionian Greeks.

It 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 tone/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.

The modern Lydian mode is a seven-tone musical scale formed from a rising pattern of pitches comprising three whole tones, a semitone, two more whole tones, and a final semitone.

Because of the importance of the major scale in modern music, the Lydian mode is often described as the scale that begins on the fourth scale degree of the major scale, or alternatively, as the major scale with the fourth scale degree raised half a step. This sequence of pitches roughly describes the scale underlying the fifth of the eight Gregorian (church) modes, known as Mode V or the authentic mode on F, theoretically using B♮ but in practice more commonly featuring B♭. The use of the B♭ as opposed to B♮ would have made such piece in the modern-day F major scale.

In the musical system of ancient Greece, an octave species (Greek: εἶδος τοῦ διὰ πασῶν, or σχῆμα τοῦ διὰ πασῶν) is a specific sequence of intervals within an octave. In Elementa harmonica, Aristoxenus classifies the species as three different genera, distinguished from each other by the largest intervals in each sequence: the diatonic, chromatic, and enharmonic genera, whose largest intervals are, respectively, a whole tone, a minor third, and a ditone; quarter tones and semitones complete the tetrachords.

The concept of octave species is very close to tonoi and akin to musical scale and mode, and was invoked in Medieval and Renaissance theory of Gregorian mode and Byzantine Octoechos.