sixthPronunciation: /sɪksθ/Translate sixth | into French | into German | into Italian | into Spanish Definition of sixth number 1constituting number six in a sequence; 6th:her sixth novel the sixth of the month to the original five categories we add a sixth the sixth finisher or position in a race or competition:he could only finish sixth chiefly British the sixth form of a school or college: the naughtiest girl in the sixth sixthly (used to introduce a sixth point or reason):sixth, given all the facts there is no logical reason why we can’t make a decision Music an interval spanning six consecutive notes in a diatonic major or minor scale, e.g. C to A ( major sixth) or A to F ( minor sixth). Music the note which is higher by a sixth than the tonic of a scale or root of a chord. 2each of six equal parts into which something is or may be divided:a sixth of the total populationDerivatives sixthly adverb sixth in other Oxford dictionaries Definition of sixth in the US English dictionary