One next in order after the sixteenth; one coming after sixteen of the same class: an ordinal numeral: as, the seventeenth, day of the month.Constituting or being one of seventeen equal parts into which a thing may be divided.n. The next in order after the sixteenth; the seventh after the tenth.n. The quotient of unity divided by seventeen; one of seventeen equal parts of a whole.n. In music, the melodic or harmonic interval of two octaves and a third; or an organ-stop giving tones at such an interval from the normal pitch of the digitals; a tierce.