Piano

A piano or pianoforte is a musical instrument classified as a keyboard, percussion, or string instrument, depending on the system of categorization used. The piano produces sound by striking steel strings with felt hammers that at once rebound allowing the string to continue vibrating at its resonant frequency. These vibrations are transmitted through the bridges to the soundboard, which amplifies them.
The piano is generally used in western music for solo performance, chamber music, and accompaniment. It is also very popular as an aid to composing and rehearsal. Even though not portable and often expensive, the piano's versatility and ubiquity has made it among the most familiar of musical instruments.
The word piano is a shortened form of the word pianoforte, which is seldom used except in formal language and resultant from the original Italian name for the instrument, gravicèmbalo col piano e forte (literally harpsichord with soft and loud). This refers to the capability of the piano to produce notes at different volumes depending on the amount of force used to press the keys.