Fifth

Part of speech: noun (n.)

1. The quotient of a unit divided by five; one of five equal parts; a fifth part.

2. The interval of three tones and a semitone, embracing five diatonic degrees of the scale; the dominant of any key.

Part of speech: adjective (a.)

1. Next in order after the fourth; -- the ordinal of five.

2. Consisting of one of five equal divisions of a thing. Fifth monarchy men (Hist.), a fanatical sect in England, of the time of the commonwealth, who maintained that there would be a fifth universal monarchy, during which Christ would reign on earth a thousand years. -- Fifth wheel, a horizontal wheel or segment above the fore axle of a carriage and beneath the body, forming an extended support to prevent careening.