pendulum

Borrowed from the neuter of Latin pendulus (“hanging”).

• IPA^(key): /ˈpɛnd͡ʒələm/
• US (some regions): IPA^(key): /ˈpɪnd͡ʒələm/

• Audio (US)

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pendulum (plural pendulums or pendula) (See usage notes.)

1. (clocks, mechanics) A body suspended from a fixed support so that it swings freely back and forth under the influence of gravity, commonly used to regulate various devices such as clocks.
   1. (by extension) The tendency of a situation to oscillate (between two extremes).
      • 2021 October 20, Industry Insider, “The wheels turn slowly”, in RAIL, number 942, page 68:

        The pendulum can be seen to be swinging in favour of rail, as with each issue of RAIL comes news of further intermodal service expansion.

2. A lamp, etc. suspended from a ceiling.
3. A watch's guard-ring by which it is attached to a chain.

• The plural form pendula is significantly rarer than pendulums; see etymology at pendula for details. However, pendula is occasionally used in physics.

• pendant

• simple harmonic motion

• “pendulum”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.

• unplumed

pendulum

1. inflection of pendulus:
   1. nominative/accusative/vocative neuter singular
   2. accusative masculine singular

• pendulum in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)