Ninth
Ninth , adjective
[From Nine; compare Anglo-Saxon nigoea.]
1.
Following the eight and preceding the tenth; coming after eight others.
2.
Constituting or being one of nine equal parts into which anything is divided.
Ninth , noun
1.
The quotient of one divided by nine; one of nine equal parts of a thing; the next after the eighth.
2.
(a) (Music) An interval containing an octave and a second.
(b)
(Music) A chord of the dominant seventh with the ninth added.