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

After that, the pendulum may swing Norrie's way, as Draper had impressive results during last year's European clay-court swing, including a run to the Madrid final and the quarter-finals in Rome.

From BBC • Mar. 16, 2026

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

From Slate • Mar. 6, 2026

We can think of climate change as a pendulum: as it intensifies, it swings from one extreme to another, hot and cold and dry and wet.

From Salon • Jan. 30, 2026

Zoph’s firing and decision to rejoin OpenAI with colleagues also marks a pendulum swing for a company that Murati, that startup’s former technology chief, had founded with 20 former OpenAI employees.

From The Wall Street Journal • Jan. 21, 2026

The kitchen clock flashed its pendulum behind its glass skirt, and it ticked like a little wooden hammer striking on an empty wooden box.

From "East of Eden" by John Steinbeck

Related Words

• timer