from The American Heritage® Dictionary of the English Language, 4th Edition

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

from Wiktionary, Creative Commons Attribution/Share-Alike License

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

from the GNU version of the Collaborative International Dictionary of English

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

from The Century Dictionary and Cyclopedia

  • Next in order or rank after the eighth, or before the tenth: an ordinal numeral: as, the ninth row; the ninth regiment.
  • Being one of nine: as, a ninth part.
  • n. A ninth part; the quotient of unity divided by nine.
  • 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.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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


Middle English ninthe, from Old English nigonthe, from nigon, nine; see newn̥ in Indo-European roots.
(American Heritage® Dictionary of the English Language, Fourth Edition)
nine +‎ -th (Wiktionary)



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