pendulum
noun1660{ds||1||}
- a body suspended from a fixed point so as to swing freely to and fro under the action of gravity and commonly used to regulate movements (as of clockwork)
- something (such as a state of affairs) that alternates between opposites
Foucault pendulum
noun1931
- a freely swinging pendulum that consists of a heavy weight hung by a long wire and that swings in a constant direction which appears to change showing that the earth rotates
Powered by Merriam-Webster