The violin, colloquially known as a fiddle, is a wooden chordophone, and is the smallest, and thus highest-pitched instrument (soprano) in regular use in the violin family. Smaller violin-type instruments exist, including the violino piccolo and the pochette, but these are virtually unused. Most violins have a hollow wooden body, and commonly have four strings, usually tuned in perfect fifths with notes G3, D4, A4, E5, and are most commonly played by drawing a bow across the strings. The violin can also be played by plucking the strings with the fingers (pizzicato) and, in specialized cases, by striking the strings with the wooden side of the bow.

A string is the vibrating element of chordophones such as the guitar, harp, piano, and the violin family, that produces sound. Strings are lengths of a flexible material that a musical instrument holds under tension so that they can vibrate freely, but with control. This is to make the string vibrate at the desired pitch, while maintaining a low profile and sufficient flexibility to play in action.