pendulum

American  

[pen-juh-luhm, pen-duh-] / ˈpɛn dʒə ləm, ˈpɛn də- /

noun

1. a body so suspended from a fixed point as to move to and fro by the action of gravity and acquired momentum.

2. Horology. a swinging lever, weighted at the lower end, for regulating the speed of a clock mechanism.

3. something that tends to move from one position, condition, etc., to the opposite extreme and then back again.

   In a democratic society, the pendulum of political thought swings left and right.

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pendulum British  

/ ˈpɛndjʊləm /

noun

1. a body mounted so that it can swing freely under the influence of gravity. It is either a bob hung on a light thread ( simple pendulum ) or a more complex structure ( compound pendulum )

2. such a device used to regulate a clockwork mechanism

3. something that changes its position, attitude, etc fairly regularly

   the pendulum of public opinion

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pendulum Scientific  

/ pĕn′jə-ləm /

1. A mass hung from a fixed support so that it is able to swing freely under the influence of gravity. Since the motion of pendulums is regular and periodic, they are often used to regulate the action of various devices, especially clocks.

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Other Word Forms

• pendulumlike
  adjective

Etymology

Origin of pendulum

1650–60; < New Latin, noun use of neuter of Latin pendulus pendulous

Explanation

A pendulum is something hanging and swinging freely from a fixed point. A grandfather clock might use for timekeeping a pendulum that swings back and forth. Pendulum comes from the Latin word pendulous, meaning "hanging down." If someone hangs a pocket watch in front of you and swings it back and forth, saying, "You're getting very sleepy," they're mimicking the movement of a pendulum. We also use the word pendulum to describe a situation moving between two poles or across a spectrum, like the balance of power in a multiparty political system.

Example Sentences

This year, it hosts events headlined by Pendulum, Fisher and Tiesto in June and July.

From BBC • Apr. 10, 2026

Probiotics maker Pendulum Therapeutics paid her $27,000 to sponsor her newsletter, and supplement company Momentous paid her nearly $40,000.

From The Wall Street Journal • Oct. 30, 2025

Perhaps the most important recent book on the politics of reform is Breaking the Pendulum, by Philip Goodman, Joshua Page, and Michelle Phelps.

From Slate • Jun. 10, 2022

Ng, who wrote the fantasy novel “Under the Pendulum Sun,” said in an interview on Wednesday that she was delighted by the decision.

From New York Times • Aug. 28, 2019

“From the old forbidden books. The Premature Burial. And the others. The Pit, the Pendulum, and the ape, the chimney, the Murders in the Rue Morgue. In a book I burned, yes!”

From "The Martian Chronicles" by Ray Bradbury

Related Words

• timer