pendulum
n. countablen. a weight that hangs from a fixed point and swings back and forth. You often see this in old clocks or used as a symbol for changing opinions.
n. a body suspended from a fixed point so as to swing freely to and fro under the action of gravity. Frequently used metaphorically to describe a situation that oscillates between two extremes.
The heavy pendulum in the old clock swings steadily.
Public opinion is like a pendulum, swinging from one political extreme to the other every few years.
The physicist adjusted the length of the wire to ensure the pendulum maintained a consistent period, demonstrating the principles of simple harmonic motion to the students.
Borrowed from the neuter of Latin pendulus (“hanging”).
Often used in the phrase 'the pendulum swings' to describe a shift in mood, politics, or fashion.