(meteorology, informal) A powerful hurricane or other major weather disturbance, especially as produced by a combination of meteorological conditions.

plural of perfect rhyme

plural of perfect set

(music) an interval equal to that of between the second and third harmonics of the harmonic series; in equal temperament, an interval of seven semitones spanning five degrees of the diatonic scale. It is enharmonically equivalent to a diminished sixth.

(mathematical analysis) A set which is equal to its set of limit points. That is, a set A is perfect if A'=A.

plural of perfect number

plural of perfect game

plural of perfect interval

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

(music) A musical interval of the Western twelve-semitone system consisting of twelve semitones and spanning eight degrees of the diatonic scale. It is enharmonically equivalent to an augmented seventh and is commonly referred to as an octave.