A major

A major (or the key of A) is a major scale based on A, with the pitches A, B, C♯, D, E, F♯, and G♯. Its key signature has three sharps.

Its relative minor is F-sharp minor and its parallel minor is A minor. The key of A major is the only key where a Neapolitan sixth chord on requires both a flat and a natural accidental.

In the treble, alto, and bass clefs, the G♯ in the key signature is placed higher than C♯. However, in the tenor clef, it would require a ledger line and so G♯ is placed lower than C♯.

Although not as rare in the symphonic literature as sharper keys, examples of symphonies in A major are not as numerous as for D major or G major. Beethoven's Symphony No. 7, Bruckner's Symphony No. 6 and Mendelssohn's Symphony No. 4 comprise a nearly complete list of symphonies in this key in the Romantic era. Mozart's Clarinet Concerto and Clarinet Quintet are both in A major, and generally Mozart was more likely to use clarinets in A major than in any other key besides E-flat major. Moreover, the climax part of Tchaikovsky's Violin Concerto (Tchaikovsky) is also A major.

Ionian mode

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 (Powers 2001a). This octave species is essentially the same as the major mode of tonal music (Jones 1974, 42).

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" (Powers 2001b, §II: "Medieval Modal Theory"), 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 (Powers 2001c).

Major

Major is a military rank of commissioned officer, with corresponding ranks existing in many military forces. When used unhyphenated, in conjunction with no other indicators, the rank is just senior to that of an army captain and right below the rank of lieutenant colonel. It is considered the most junior of the field officer ranks.

Majors are typically assigned as specialized executive or operations officers for battalion-sized units of 300 to 1,200 soldiers. In some militaries, notably France and Ireland, the rank of major is referred to as commandant, while in others it is known as captain-major. It is also used in some police forces and other paramilitary rank structures, such as the New York State Police, New Jersey State Police and several others. As a police rank, Major roughly corresponds to the UK rank of Superintendent.

When used in hyphenated or combined fashion, the term can also imply seniority at other levels of rank, including general-major or major general, denoting a mid-level general officer, and sergeant major, denoting the most senior NCO of a military unit. The term Major can also be used with a hyphen to denote the leader of a military band such as in pipe-major or drum-major.