A mandolin is a stringed musical instrument. Mandolins have 8 strings, in 4 pairs. Each pair of strings is tuned in unison, and are a fifth apart from adjacent pairs, giving an identical tuning to a violin (G-D-A-E low-to-high). Unlike a violin, the neck of a mandolin is fretted and it is typically played with a plectrum.
Like the guitar the mandolin is a poorly sustaining (a note can not be maintained for an arbitary time as with a violin) instrument. Its higher pitch makes this problem more severe than with the guitar, and as a result use of tremolo (rapid picking on a single note) is common place.
Mandolins come in a few forms. The more traditional roundback has a vaulted back made of a number of strips of wood in a bowl formation, similar to a lute. The flatback mandolin derives from the cittern. The carved top instrument was introduced by the Gibson company. These use the best of violin making techniques and guitar making production.