Mandolin
Mandolins have eight strings tuned in pairs. From lowest to highest the strings are GG-DD-AA-EE. This is the same open string tuning as a violin. The sound of a mandolin is a little brighter than the larger guitar.
Mandolins have frets that are used to shorten the length of the vibrating string in order to produce notes above the open strings.
Mandolins can be found in bluegrass bands and other folk music ensembles.
Study the image provided and listen to the sound sample of the mandolin to gain an understanding of this instrument.
Listen to a sample of the mandolin: