WordWeb Online

1. Coming next after the eighth and just before the tenth in position
   - 9th

1. Position nine in a countable series of things
   "going into the ninth they were a run ahead"
    
2. One part in nine equal parts
   - one-ninth

Derived forms: ninths

See also: ordinal

Type of: common fraction, rank, simple fraction, vulgar fraction [Brit]

Encyclopedia: Ninth