perpetuum mobile

Meanings

1. A perpetual motion machine.
2. Pieces of music, or parts of pieces, characterised by a continuous steady stream of notes, usually at a rapid tempo.
3. Whole pieces, or large parts of pieces, which are to be played repeatedly, often an indefinite number of times.

Etymology

From Latin perpetuum (neutral inflection of perpetuus “perpetual”) + Latin mōbile (neutrum of mōbilis “mobile, moving”), used together as a noun, thus literally meaning “perpetual mover”. Although often said to literally mean “perpetual motion”, the latter in Latin is mōtus perpetuus. A perpetuum mobile is a device that exhibits perpetual motion.