A body so suspended from a fixed point as to swing freely to and fro by the alternate action of gravity and momentum. It is used to regulate the movements of clockwork and other machinery.
- A body suspended from a fixed support so that it swings freely back and forth under the influence of gravity, commonly used to regulate various devices, especially clocks. Also called simple pendulum.
- Something that swings back and forth from one course, opinion, or condition to another: the pendulum of public opinion.