—n.
1 the position in a sequence corresponding to the number 9 in the sequence 1-9.
2 something occupying this position.
3 each of nine equal parts of a thing.
4 Mus. a an interval or chord spanning nine consecutive notes in the diatonic scale (e.g. C to D an octave higher). b a note separated from another by this interval.
—adj. that is the ninth.
Derivatives:
ninthly adv.
Useful english dictionary. 2012.