A device for holding a moveable member fixed in one of two or more desired positions; allowing for manual selection of the position. Example: allowing a mechanism to start or stop.
diapason pipe
The basic tone of the church pipe organ; smooth, steady sounding pipes richer in tone than flutes but not as raspy as strings nor as bright as brilliant reed pipes.
diminuendo
(often seen abbreviated as dim.) Same as decrescendo (also listed in this Glossary).
disc music box
Music box on which a disc causes a music comb to be plucked by means of intervening star wheels (usually) or levers. One of two main music box types (the other: the cylinder music box). Popular during the 1890s and early 1900s. Made by Polyphon, Regina, Symphonion, and others.
disc shifting musical box
A musical box designed to play two tunes in two revolutions of the disc by means of laterally shifting the disc between tunes. The New Century and Sirion boxes are the best known of this type.