sostenuto pedal

A sustain or sustaining pedal (also damper pedal or loud pedal) is the most commonly used pedal in a modern piano. It is typically the rightmost of two or three pedals. When pressed, the sustain pedal "sustains" all the strings on the piano, removing the dampers from all strings and allowing them to vibrate freely. This serves two purposes. First, it assists the pianist in producing a legato (playing smoothly connected notes) in passages where no fingering is available to make this otherwise possible. Secondly, raising the damper pedal causes all the strings to vibrate sympathetically with whichever notes are being played, which greatly enriches the piano's tone.
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