sostenuto
Sustained; each note held to its full value.
In Depth
Sostenuto means sustained — each note should be held for its full written value, with no shortening or clipping. The marking calls for a broad, singing quality where the sound is maintained evenly throughout each note's duration. On the piano, the sostenuto [pedal](/term/sostenuto%20pedal) (the middle pedal on a grand piano) holds open only the dampers of notes that are depressed at the moment the pedal is engaged, allowing those specific notes to sustain while subsequent notes are unaffected. This selective sustain is different from the damper pedal's blanket effect and is used for long bass notes or chords that need to ring while the hands play other material.
The sostenuto [pedal](/term/sostenuto%20pedal) on a grand piano was invented in 1844 but didn't become standard until decades later. Many pianists today still rarely use it, despite its unique selective-sustain capability.