ninth
Pronunciation: /ˈnʌɪnθ/
ordinal number
- 1constituting number nine in a sequence; 9th: the ninth century the ninth of March
- the ninth finisher or position in a race or competition: he came in ninth
- Music an interval spanning nine consecutive notes in a diatonic scale.
- Music the note which is higher by a ninth than the tonic of a diatonic scale or root of a chord.
- Music a chord in which the ninth note of the scale forms an important component.

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Remember that ninth begins with nin-.