ninth definition by Webster's New World
- preceded by eight others in a series; 9th
- designating any of the nine equal parts of something
Origin: Middle English ninthe ; from Old English nigonthe: see nine and amp; -th
- the one following the eighth
- any of the nine equal parts of something;
- an interval in pitch of an octave and a second
- a tone separated from another by such an interval
- the combination of two such tones
- ninthly adverb
ninth definition by American Heritage Dictionary
- The ordinal number matching the number nine in a series.
- One of nine equal parts.
- Music a. A harmonic or melodic interval of an octave and a second.b. The tone at the upper limit of such an interval.c. A chord consisting of a root with its third, seventh, and ninth.
Origin: Middle English ninthe, from Old English nigonthe, from nigon, nine; see newṇ in Indo-European roots.
- ninth adverb & adj.