The Collaborative International Dictionary of English v.0.48:

nine \nine\ (n[imac]n), a. [OE. nine, nihen, AS. nigon, nigan;
   akin to D. & LG. negen, OS. & OFries. nigun, OHG. niun, G.
   neun, Icel. n[imac]u, sw. nio, Dan. ni, Goth. niun, Ir. &
   Gael. naoi, W. naw, L. novem, Gr. 'enne`a, Skr. navan; of
   unknown origin. [root]307. Cf. Novembeer.]
   Eight and one more; one less than ten; as, nine miles.
   [1913 Webster]

   Nine men's morris. See Morris.

   Nine points circle (Geom.), a circle so related to any
      given triangle as to pass through the three points in
      which the perpendiculars from the angles of the triangle
      upon the opposite sides (or the sides produced) meet the
      sides. It also passes through the three middle points of
      the sides of the triangle and through the three middle
      points of those parts of the perpendiculars that are
      between their common point of meeting and the angles of
      the triangle. The circle is hence called the nine points
      circle or six points circle.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Nine \Nine\, n.
   1. The number greater than eight by a unit; nine units or
      objects.
      [1913 Webster]

   2. A symbol representing nine units, as 9 or ix.
      [1913 Webster]

   3. A group of nine people; as, the New York nine (a baseball
      team).
      [PJC]

   The Nine, the nine Muses.
      [1913 Webster]

WordNet (r) 3.0 (2006):

nine
    adj 1: denoting a quantity consisting of one more than eight and
           one less than ten [syn: nine, 9, ix]
    n 1: the cardinal number that is the sum of eight and one [syn:
         nine, 9, IX, niner, Nina from Carolina, ennead]
    2: a team of professional baseball players who play and travel
       together; "each club played six home games with teams in its
       own division" [syn: baseball club, ball club, club,
       nine]
    3: one of four playing cards in a deck with nine pips on the
       face [syn: nine-spot, nine]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "nine":
   Nina from Carolina, cast, company, complement, crew, eight, eleven,
   ennead, enneastyle, first string, first team, five, nonage,
   nonagon, nonuplet, novena, platoon, reserves, rowing crew,
   second string, second team, squad, string, team, third string,
   varsity