A mandolin is a small stringed musical instrument with a rounded body and eight strings arranged in four pairs. When you pluck or strum these paired strings with a pick, the mandolin produces a bright, ringing sound that cuts through other instruments in a band.

The mandolin looks somewhat like a tiny guitar, but its back is rounded like half a pear, and its strings are metal rather than nylon. Musicians often play it with a rapid back-and-forth picking technique called tremolo that creates a shimmering, sustained sound. You might hear mandolins in bluegrass music, Italian folk songs, or even rock bands looking for a distinctive acoustic sound.

The instrument came from Italy in the 1700s and became especially popular in American folk and bluegrass music. When Bill Monroe developed bluegrass as a musical style in the 1940s, his lightning-fast mandolin playing helped make the instrument essential to the genre. If you've heard lively fiddle music at a folk festival or barn dance, chances are good a mandolin was part of the band, adding its cheerful, metallic jangle to the mix.