ninth Syllabification: (ninth)Pronunciation: /nīnTH/Translate ninth | into French | into German | into Italian | into Spanish Definition of ninth number constituting number nine in a sequence; 9th:the ninth century the ninth of March (a ninth/one ninth) each of nine equal parts into which something is or may be divided. the ninth finisher or position in a race or competition:he came in ninth the ninth and final inning of a regulation baseball game:he was rocked for five runs in the ninth Music an interval spanning nine consecutive notes in a diatonic scale. Music the note that is nine notes higher than the tonic of a diatonic scale or root of a chord. Music a chord in which the ninth note above the root forms an important component. Derivatives ninthly adverb Remember that ninth begins with nin-.ninth in other Oxford dictionaries Definition of ninth in the British & World English dictionary