What is "minor seventh"

n. (context music English) A musical interval of the Western twelve-semitone system consisting of ten semitone and spanning seven degrees of the diatonic scale. It is one semitone narrower than a major seventh and enharmonically equivalent to an augmented sixth.

In classical music from Western culture, a seventh is a musical interval encompassing seven staff positions, and the minor seventh is one of two commonly occurring sevenths. It is qualified as minor because it is the smaller of the two: the minor seventh spans ten semitones, the major seventh eleven. For example, the interval from A to G is a minor seventh, as the note G lies ten semitones above A, and there are seven staff positions from A to G. Diminished and augmented sevenths span the same number of staff positions, but consist of a different number of semitones (nine and twelve).

Minor seventh intervals are rarely featured in melodies (and especially in their openings) but occur more often than major sevenths. The best-known example, in part due to its frequent use in theory classes, is found between the first two words of the phrase "There's a place for us" in the song " Somewhere" in West Side Story. Another well-known example occurs between the first two notes of the introduction to the main theme music from Star Trek: The Original Series theme.

The most common occurrence of the minor seventh is built on the root of the prevailing key's dominant triad, producing the all-important dominant seventh chord.

Consonance and dissonance are relative, depending on context, the minor seventh being defined as a dissonance requiring resolution to a consonance.