pendulums <p>Refers to masses, usually long in relation to their width, suspended from a fixed point, and often having a weight on the free end, and able to swing in an arc back and forth by the actions of gravity and acquired momentum; sometimes used for regulating the speed of clock mechanisms.</p> <p>Source: AAT</p> <p>http://vocab.getty.edu/page/aat/300235975</p>