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

Derived 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

The U.S. economy has never occupied either of these extremes; over the decades, the pendulum has swung between regulation and competition.

From The Wall Street Journal • May 31, 2026

In that sense, things are moving in Visa’s favor, he said, “but Mastercard is faster growing, and the pendulum could swing back.”

From MarketWatch • May 25, 2026

But Monnier at Citi Wealth argues that the pendulum is swinging back a bit as families realize that doing their own due diligence on a company is a lot of work.

From Barron's • May 23, 2026

The story of the labor market, which can sometimes resemble a pendulum, is more complicated.

From Slate • Mar. 6, 2026

But, over time, the middle ground that people like Sprat and Bentley had sought to occupy between superstition and rationalism became increasingly embattled, and the pendulum began to swing the other way.

From "The Invention of Science" by David Wootton

Related Words

• timer