damper pedal

See more synonyms for damper pedal on Thesaurus.com
noun Music.
  1. a pedal on a piano that when depressed with the foot raises the dampers and permits the strings to vibrate and sustain the tone.
Also called loud pedal, reverberation pedal, sustaining pedal.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for sustaining pedal

sustaining pedal

noun
  1. music a foot-operated lever on a piano, usually the right one of two, that keeps the dampers raised from the strings when keys are released, allowing them to continue to vibrateCompare soft-pedal (def. 3)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012