Scale length is a measurement used to describe the size of string instruments like guitars and violins. It is the distance from the top of the strings at the nut, which is the grooved piece at the end of the neck, to the end of the strings at the bridge, which is the piece that holds the strings up. A longer scale length means there is more distance from the nut to the bridge, and generally results in a louder, fuller sound because the strings are stretched further. A shorter scale length gives a quieter and less resonant sound.