ninth
n. countablen. the distance between the first note and the ninth note in a musical scale. It sounds like an octave plus one extra step.
n. a musical interval spanning an octave and a major or minor second. Often used as an extension in jazz harmony to add tension or color to a chord.
The pianist added a ninth to the chord for a richer sound.
In jazz theory, adding a major ninth to a dominant chord creates a sophisticated and open harmonic texture.
The composer's frequent use of the minor ninth creates a sense of unresolved tension that defines the melancholic atmosphere of the second movement.
From Middle English nynthe, nynte, from Old English niġoþa, from Proto-Germanic *newundô; the -n- was reinserted by analogy with nine. Equivalent to nine + -th (ordinal suffix).
Commonly used in the context of chord construction and interval identification.