The Tar is a simple and ancient frame drum.  A round frame, usually made of wood, is fitted with a drum head, usually made from an animal skin.  The Oud is a guitar-like instrument typically with eleven strings.  It does not have frets on the neck like a guitar.  Frets are the ridges on the neck of the guitar that help a player find the notes.  The oud is recognizable by the deep, round, pear-shaped body and bent neck.  Both the Tar and Oud are used throughout the Middle East and Northern Africa.