The guitar's ancestors include the gittern, the vihuela, the four- course Renaissance guitar, and the five-course baroque guitar, all of which contributed to the development of the modern six-string instrument. Steel guitar strings were introduced near the end of the nineteenth century in the United States nylon strings came in the 1940s.
Historically, a guitar was constructed from wood with its strings made of catgut. The guitar is classified as a chordophone – meaning the sound is produced by a vibrating string stretched between two fixed points. The sound of the guitar is projected either acoustically, by means of a resonant chamber on the instrument, or amplified by an electronic pickup and an amplifier. A plectrum or individual finger picks may also be used to strike the strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected strings against frets with the fingers of the opposite hand. The guitar is a fretted musical instrument that typically has six strings.
