I’m posting a link here to a blog post over on Portland Piano Company‘s website.
Here is a teaser quote from their post “What is a Piano?” You can read their article here.
“The two main requirements of a piano action are that it must multiply the power of a person’s fingers to strike the strings and the hammer must fall back off the string slightly after the strike so that it does not mute the string. Otherwise, the instrument would be called a pianomuffle instead of a pianoforte. ”