What Is a Piano? How It Works, Types, History & Buying Guide

The piano is a keyboard instrument in which pressing a key sets a felt-covered hammer in motion to strike one or more strings. Its name comes from gravicembalo col piano e forte—a keyboard instrument capable of playing softly and loudly. That control over dynamics is what separated the early piano from instruments such as the harpsichord.

Quick answer: an acoustic piano combines a keyboard, action, hammers, strings, dampers, soundboard, frame, and pedals. Modern standard instruments commonly have 88 keys, but historical, compact, and extended-range models may have fewer or more. Grand, upright, digital, and hybrid pianos suit different rooms, budgets, practice needs, and performance goals.

How Does a Piano Produce Sound?

1. The key moves the action. A system of levers transfers the player’s motion toward the hammer.
2. The hammer accelerates and escapes. The mechanism lets the hammer strike the strings and immediately fall away instead of remaining pressed against them.
3. The strings vibrate. Depending on register, a note may use one, two, or three strings.
4. The soundboard amplifies the vibration. The bridge transfers string energy to the wooden soundboard, which moves a much larger volume of air.
5. The damper controls duration. When the key is released, the damper normally returns to the strings and stops them, unless a pedal keeps them free.

The speed with which the player depresses the key affects hammer velocity and therefore loudness and tone. This touch sensitivity is fundamental to piano technique.