DIMINUTION

'Diminution', from Italian ''diminuimento'', is a musical term used to mean different things in the context of melodies and intervals or chords.
A melody or series of notes is ''diminished'' if the lengths of the notes are shortened (this is opposed to ''augmentation'', where the notes are lengthened). A melody originally consisting of four crotchets (quarter-notes) for example, is diminished if it later appears with four quavers (eighth-notes) instead. This technique is often used in contrapuntal music. It gives rise to the "canon in diminution", in which the notes in the following voice are shorter than those in the leading.
An interval is ''diminished'' if it is narrowed by a chromatic semitone; a diminished chord is one which contains a diminished interval. Thus a diminished fifth, for example, is a chromatic semitone narrower than the perfect fifth, and a diminished triad is a minor triad whose fifth note has been lowered a chromatic semitone. The opposite is ''augmented''.
In Schenkerian analysis a diminution is a division, rather than a diminishing is a prolongation or expansion, "the process by which an interval formed by notes of longer value is expressed in notes of smaller value," see nonchord tone.
'Diminution' is also a satirical technique. It reduces the size of something in order that it may be made to appear ludicrous, or in order to be closely examined. For example, if the Canadian Members of Parliament are portrayed as squabbling, spoiled little boys and girls, this would be diminution. A diminutive satire is Gulliver's Travels.