(1):
(a.) Consisting of one of five equal divisions of a thing.
(2):
(n.) The interval of three tones and a semitone, embracing five diatonic degrees of the scale; the dominant of any key.
(3):
(n.) The quotient of a unit divided by five; one of five equal parts; a fifth part.
(4):
(a.) Next in order after the fourth; - the ordinal of five.