Any system which, when set in motion, creates a force which inhibits that same motion, is said to exhibit damping. Damping forces are usually created by friction, either aerodynamic (external) or material (internal). *(Most true damping with regard to fishing rods is caused by air friction. Some internal material friction does exist, however.) Although most often incorrectly used within the confines of rod building, the term is generally used and understood to describe how long a rod takes to return to straight or stop, after being cast or flexed, i.e "This rod damps quickly."