In classical music, a third is a musical interval encompassing three staff positions (see

Interval number In music theory, an interval is a difference in pitch between two sounds. An interval may be described as horizontal, linear, or melodic if it refers to successively sounding tones, such as two adjacent pitches in a melody, and vertical or h ...

for more details), and the major third () is a third spanning four

semitone A semitone, also called a half step or a half tone, is the smallest musical interval commonly used in Western tonal music, and it is considered the most dissonant when sounded harmonically. It is defined as the interval between two adjacent no ...

s. Forte, Allen (1979). ''Tonal Harmony in Concept and Practice'', p.8. Holt, Rinehart, and Winston. Third edition . "A large 3rd, or ''major 3rd'' (M3) encompassing four half steps." Along with the

minor third In music theory, a minor third is a musical interval that encompasses three half steps, or semitones. Staff notation represents the minor third as encompassing three staff positions (see: interval number). The minor third is one of two com ...

, 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

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 The major scale (or Ionian mode) is one of the most commonly used musical scales, especially in Western music. It is one of the diatonic scales. Like many musical scales, it is made up of seven notes: the eighth duplicates the first at double ...

is so named because of the presence of this interval between its tonic and mediant (1st and 3rd) scale degrees. The

major chord In music theory Music theory is the study of the practices and possibilities of music. ''The Oxford Companion to Music'' describes three interrelated uses of the term "music theory". The first is the " rudiments", that are needed to understan ...

also takes its name from the presence of this interval built on the chord's

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the su ...

(provided that the interval of a perfect fifth from the root is also present or implied). A major third is slightly different in different musical tunings: in just intonation it 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

s, a ratio of 2^1/3:1 (about 1.2599) or 400 cents, 13.69 cents wider than the 5:4 ratio. The older concept of a

ditone In music, a ditone (, from , "of two tones") is the interval of a major third. The size of a ditone varies according to the sizes of the two tones of which it is compounded. The largest is the Pythagorean ditone, with a ratio of 81:64, also cal ...

(two 9:8 major seconds) made a dissonantly wide major third with the ratio 81:64 (about 1.2656) or 408 cents (). The septimal major third is 9:7 (435 cents), the undecimal major third is 14:11 (418 cents), and the tridecimal major third is 13:10 (452 cents). 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 third, the 125th subharmonic, is less than an octave. For example, three 5:4 major thirds from C is B (C to E to G to B) (B

= 5^3/2^6= 125/64

). The difference between this just-tuned B and C, like that between G and A, is called the "enharmonic diesis", about 41 cents (the inversion of the 125/64 interval:

128/125 = 2^7/5^3

)). The major third is classed as an imperfect consonance and is considered one of the most consonant intervals after the

unison In music, unison is two or more musical parts that sound either the same pitch or pitches separated by intervals of one or more octaves, usually at the same time. ''Rhythmic unison'' is another term for homorhythm. Definition Unison or per ...

, octave, perfect fifth, and

perfect fourth A fourth is a musical interval encompassing four staff positions in the music notation of Western culture, and a perfect fourth () is the fourth spanning five semitones (half steps, or half tones). For example, the ascending interval from C to ...

. In the

common practice period In European art music, the common-practice period is the era of the tonal system. Most of its features persisted from the mid-Baroque period through the Classical and Romantic periods, roughly from 1650 to 1900. There was much stylistic evoluti ...

, thirds were considered interesting and dynamic consonances along with their inverses the sixths, but in

medieval times In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire an ...

they were considered dissonances unusable in a stable final sonority. A

diminished fourth In classical music from Western culture, a diminished fourth () is an interval produced by narrowing a perfect fourth by a chromatic semitone.Benward & Saker (2003). ''Music: In Theory and Practice, Vol. I'', p.54. . Specific example of an d4 ...

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 In music theory, the minor scale is three scale patterns – the natural minor scale (or Aeolian mode), the harmonic minor scale, and the melodic minor scale (ascending or descending) – rather than just two as with the major scale, which al ...

. The major third is used in

guitar tunings Guitar tunings are the assignment of pitches to the open strings of guitars, including acoustic guitars, electric guitars, and classical guitars. Tunings are described by the particular pitches that are made by notes in Western music. By ...

. For the

standard tuning In music, standard tuning refers to the typical tuning of a string instrument. This notion is contrary to that of scordatura, i.e. an alternate tuning designated to modify either the timbre or technical capabilities of the desired instrument. Viol ...

, 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 Among alternative tunings for guitar, a major-thirds tuning is a regular tuning in which each interval between successive open strings is a major third ("M3" in musical abbreviation). Other names for major-thirds tuning include major-third tun ...

, each of the intervals are major thirds.

Interval sounds

* Minor thirds: * Major thirds

References

{{Intervals Thirds (music) Major intervals ru:Терция (интервал)#Разновидности терции

Interval sounds

See also

References