A musical interval of the Western twelve-semitone system consisting of five semitones and spanning four degrees of the diatonic scale. It is enharmonically equivalent to an augmented third.

plural of perfect fourth

plural of perfect fifth

plural of perfect interval

(music) an interval that is either a unison, fourth, fifth, or an octave

(music) an interval that has no difference between two notes

plural of perfect unison

plural of perfect octave

plural of perfecting press

A press in which the printing on both sides of the paper is completed in one passage through the machine.