What is "major third"

Major \Ma"jor\, [L. major, compar. of magnus great: cf. F. majeur. Cf. Master, Mayor, Magnitude, More, a.]

1. Greater in number, quantity, or extent; as, the major part of the assembly; the major part of the revenue; the major part of the territory.

2. Of greater dignity; more important.
   --Shak.

3. Of full legal age; adult. [Obs.]

4. (Mus.) Greater by a semitone, either in interval or in difference of pitch from another tone.

   Major key (Mus.), a key in which one and two, two and three, four and five, five and six and seven, make major seconds, and three and four, and seven and eight, make minor seconds.

   Major offense (Law), an offense of a greater degree which contains a lesser offense, as murder and robbery include assault.

   Major scale (Mus.), the natural diatonic scale, which has semitones between the third and fourth, and seventh and fourth, and seventh and eighth degrees; the scale of the major mode, of which the third is major. See Scale, and Diatonic.

   Major second (Mus.), a second between whose tones is a difference in pitch of a step.

   Major sixth (Mus.), a sixth of four steps and a half step. In major keys the third and sixth from the key tone are major. Major keys and intervals, as distinguished from minors, are more cheerful.

   Major third (Mus.), a third of two steps.

Third \Third\, n.

1. The quotient of a unit divided by three; one of three equal parts into which anything is divided.

2. The sixtieth part of a second of time.

3. (Mus.) The third tone of the scale; the mediant.

4. pl. (Law) The third part of the estate of a deceased husband, which, by some local laws, the widow is entitled to enjoy during her life.

   Major third (Mus.), an interval of two tones.

   Minor third (Mus.), an interval of a tone and a half.

n. (context music English) A musical interval of the Western twelve-semitone system consisting of four semitone and spanning three degrees of the diatonic scale. major scale are so named because of the major third interval between the tonic and mediant of a major tonic triad. It is enharmonically equivalent to a diminished fourth.

In classical music from Western culture, a third is a musical interval encompassing three staff positions (see Interval number for more details), and the major third is a third spanning four semitones. Along with the minor third, the major third is one of two commonly occurring thirds. It is qualified as major because it is the larger of the two: the major third spans four semitones, the minor third three. For example, the interval from C to E is a major third, as the note E lies four semitones above C, and there are three staff positions from C to E. Diminished and augmented thirds span the same number of staff positions, but consist of a different number of semitones (two and five).

The major third may be derived from the harmonic series as the interval between the fourth and fifth harmonics. The major scale is so named because of the presence of this interval between its tonic and mediant (1st and 3rd) scale degrees. The major chord also takes its name from the presence of this interval built on the chord's root (provided that the interval of a perfect fifth from the root is also present or implied).

A major third in just intonation corresponds to a pitch ratio of 5:4 (fifth harmonic in relation to the fourth) or 386.31 cents; in equal temperament, a major third is equal to four semitones, a ratio of 2:1 (about 1.2599) or 400 cents, 13.69 cents wider than the 5:4 ratio. The older concept of a ditone (two 9:8 major seconds) made a dissonantly wide major third with the ratio 81:64 . The septimal major third is 9:7, the undecimal major third is 14:11, and the tridecimal major third is 13:10.

A helpful way to recognize a major third is to hum the first two notes of " Kumbaya" or of " When the Saints Go Marching In". A descending major third is heard at the starts of " Goodnight, Ladies" and " Swing Low, Sweet Chariot".

In equal temperament three major thirds in a row are equal to an octave (for example, A to C, C to E, and E to G; G and A represent the same note). This is sometimes called the " circle of thirds". In just intonation, however, three 5:4 major thirds are less than an octave. For example, three 5:4 major thirds from C is B (C to E to G to B). The difference between this just-tuned B and C, like that between G and A, is called a diesis, about 41 cents.

The major third is classed as an imperfect consonance and is considered one of the most consonant intervals after the unison, octave, perfect fifth, and perfect fourth. In the common practice period, thirds were considered interesting and dynamic consonances along with their inverses the sixths, but in medieval times they were considered dissonances unusable in a stable final sonority.

A diminished fourth is enharmonically equivalent to a major third (that is, it spans the same number of semitones). For example, B–D is a major third; but if the same pitches are spelled B and E, the interval is instead a diminished fourth. B–E occurs in the C harmonic minor scale.

The major third is used in guitar tunings. For the standard tuning, only the interval between the 3rd and 2nd strings (G to B, respectively) is a major third; each of the intervals between the other pairs of consecutive strings is a perfect fourth. In an alternative tuning, the major-thirds tuning, each of the intervals are major thirds.