fourth

1. The fourth tone of a scale, the subdominant. 2. An interval containing four tones, the extremes included, as d-g, the ratio being 3: 4. Fourths are perfect and imperfect rather than major or minor. An augmented (superfluous, extreme, sharp or pluperfect) fourth is one whose upper tone has been raised a_half step, or its lower lowered. A diminished (imperfect, false, minor or defective) fourth one whose upper tone has been lowered half a step or its lower raised (cf. r1rTH). -Chord of the second and fourth, chord of the 3d, 4th, and 6th, chord of the 4th and 6th. Vide cHorp.