Noun
action consisting of a system of levers that move a felt hammer to strike the strings when a key is depressed
Source: WordNetCristofori's piano action was a model for the many approaches to piano actions that followed. Source: Internet
This shifts the entire piano action so the pianist can play music written in one key so that it sounds in a different key. Source: Internet
Unlike in a piano action, the tangent does not rebound from the string; rather, it stays in contact with the string as long as the key is held, acting as both the nut and as the initiator of sound. Source: Internet