ninth

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The ordinal number matching the number nine in a series.
2. n. One of nine equal parts.
3. n. Music A harmonic or melodic interval of an octave and a second.
4. n. Music The tone at the upper limit of such an interval.
5. n. Music A chord consisting of a root with its third, seventh, and ninth.

Century Dictionary and Cyclopedia

1. Next in order or rank after the eighth, or before the tenth: an ordinal numeral: as, the ninth row; the ninth regiment.
2. Being one of nine: as, a ninth part.
3. n. A ninth part; the quotient of unity divided by nine.
4. n. In music, the interval, whether melodic or harmonic, between any tone and a tone one octave and one degree distant from it; also, a tone distant by such an interval from a given tone; a compound second.

Wiktionary

1. adj. The ordinal form of number nine.
2. n. The person or thing in the ninth position.
3. n. One of nine equal parts of a whole.

GNU Webster's 1913

1. adj. Following the eight and preceding the tenth; coming after eight others.
2. adj. Constituting or being one of nine equal parts into which anything is divided.
3. n. The quotient of one divided by nine; one of nine equal parts of a thing; the next after the eighth.
4. n. An interval containing an octave and a second.
5. n. A chord of the dominant seventh with the ninth added.

WordNet 3.0

1. adj. coming next after the eighth and just before the tenth in position
2. n. position nine in a countable series of things
3. n. one part in nine equal parts