GuitarPlucked, fretted string instrument. It may be called the classical guitar, the Spanish guitar (because of its origins), or the acoustic guitar (to differentiate it from the electric guitar). A musical instrument with a body generally shaped like a figure eight, a long fretted neck, and strings. The fingerboard has frets (strips of metal showing where to place the finger to obtain different notes), and the 6 or 12 strings are plucked or strummed with the fingers or a plectrum.