A stringed musical instrument in which the strings are struck by wooden hammers that are coated with a softer material. It is played with a keyboard, which is a row of keys that a player presses down or strikes with the fingers and thumbs of both hands to make the hammers strike the strings.

There are four main types of pianos:

• grand piano - constructed with a frame and strings in horizontal position

• upright piano - also called a vertical piano due to vertical position of strings. Upright pianos are more compact due to the vertical construction of the frame.

• electric piano - strings are often replaced by metal tines and are combined with a pick-up similar to a guitar pick-up. Then, a signal has to go to an amplification unit.

• digital piano - non-acoustic type of a piano without strings. Within digital pianos, a digital sampling technology is used in order to reproduce the sound of each piano note accurately. Digital pianos must be connected to a power amplifier and speaker to produce sound, however, many digital pianos include a built-in amplifier and speakers