n. & adj.
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. ninthly adv.