guitar, musical instrument related to the lute, modern guitars normally having six strings that are plucked with the fingers or strummed with a pick. Earlier versions had pairs of strings like the lute. The guitar usually has a flat back, sides that curve inward to form a waist, and a fretted neck. Other forms of the guitar include the 12-stringed guitar; the steel guitar, played with a metal bar to produce a sliding tone; the electric guitar; and the 4-stringed bass guitar, which, like the electric guitar, is a fixture of rock music and is electronically amplified. The traditional classical, as opposed to electric guitar, appeared as early as the 12th cent. in Spain, the country with which it is particularly associated. It was very popular there in the 16th cent., when much music was written for it. The composer Fernando Sor (1778-1839) was a brilliant guitarist who wrote many important works for that instrument. In the late 19th cent. there was revived interest in the guitar, aroused largely by the playing of Francisco Tárrega (1852-1909), one of the greatest guitar players of all time. Andrés Segovia was one of the foremost contemporary classical guitarists; he did much to stimulate interest in the instrument and its repertory, especially in 16th-century music.

Plucked stringed instrument. It normally has six strings, a fretted fingerboard, and a soundbox with a pronounced waist. It probably originated in Spain in the early 16th century. By 1800 it was being strung with six single strings; 19th-century innovations gave it its modern form. Modern classical guitar technique owes much to Francisco Tárrega (1852–1909), and Andrés Segovia gave the instrument prominence in the concert hall. However, it has always been primarily an amateur's instrument, and it remains an important folk instrument in many countries. The 12-string guitar is strung in six double courses. The Hawaiian, or steel, guitar is held horizontally and the strings are stopped by the pressure of a metal bar, producing a sweet glissando tone. The electric guitar represented a major development. Electric pickups were attached to the acoustic guitar in the 1920s. In the 1940s Les Paul invented the solid-body guitar; lacking a soundbox, it transmits only the string vibrations. With its long-sustained notes, affinity for strong amplification, and capacity for producing wailing melodic lines as well as harshly percussive rhythms, it soon became the principal instrument of Western popular music.

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