Definition of pendulum in English:



  • 1A weight hung from a fixed point so that it can swing freely, especially a rod with a weight at the end that regulates the mechanism of a clock.

    • ‘Two girls sat on opposite bunk beds, both on the top letting their legs dangle over the sides and swinging their feet like fast swinging pendulums.’
    • ‘Two sensors help keep the clock accurate by checking the swing of the pendulum using the lights that power it.’
    • ‘The pendulum of the grandfather clock sways as the second hand moves seemingly unbearably slow.’
    • ‘Passion results when they collide, swing apart, and collide once again, as long as the pendulums don't swing apart so violently that their connection breaks and they fly off in opposite directions.’
    • ‘It was hot, sticky day in the French capital and the match began with the stately tempo of a grandfather clock's pendulum.’
    • ‘In contrast, when the pendulums swing in opposite directions at the same frequency, the platform doesn't move.’
    • ‘If I then release the weight the pendulum begins to swing.’
    • ‘This motion can be described in terms of a differential equation, and in the case of small swings of the pendulum this equation can be solved to find the time of the swing.’
    • ‘He constructed the first pendulum clock with a device to ensure that the pendulum was isochronous by forcing the pendulum to swing in a cycloid arc.’
    • ‘Now suppose that the pendulums of the two clocks were arrested.’
    • ‘But somewhere in the middle of the pendulums swing, individuals who are tenacious, perceptive, or lucky may glean both freedom and wisdom from social changes.’
    • ‘There is some evidence that the pendulum is swinging in that direction.’
    • ‘With his interest in the measurement of time, he then discovered the pendulum could be a regulator of clocks.’
    • ‘He used the involute of a circle in his first pendulum clock in an attempt to force the pendulum to swing in the path of a cycloid.’
    • ‘The ticking of a clock filtered through the silence, a pendulum swinging lightly on the side of the dimly lit room which was basked in a dull, blue light.’
    • ‘It's the same phenomenon that causes swinging pendulums to synchronize when they are close together, or that causes a tuning fork to vibrate sympathetically when another tuning fork of the same pitch is struck.’
    • ‘The early pendulum clocks had short pendulums.’
    • ‘Until the 1920s, the most accurate timepieces depended on the regular swing of a pendulum.’
    • ‘This dislodged the pendulum, causing the clock to strike the twelfth time.’
    • ‘You see, all mechanical clocks are driven by a weight, like a pendulum, or a tightly wound spring.’
    1. 1.1 Used to refer to the tendency of a situation to oscillate between one extreme and another.
      ‘the pendulum of fashion’
      • ‘Sometimes the pendulum is at one extreme or another as the result of the push of forces for change.’
      • ‘You can see how the pendulum between these two extremes has swung by looking at e-mail.’
      • ‘Those are the days when the cycling mental pendulum is at its polar extremes.’
      • ‘This must put him near the low point in the pendulum of architectural fashion.’
      • ‘Although he wrongly concluded that the periods of oscillation of two pendulums were in the same ratio as their lengths, he later corrected the error.’

The use of the pendulum for regulating clocks depends on the principle, discovered by Galileo c.1602, that for small amplitudes the time of oscillation of a pendulum depends only on its length. A freely suspended pendulum resists changes in its plane of oscillation, a fact employed by Jean Foucault in 1851 to demonstrate the earth's rotation


Mid 17th century: from Latin, neuter (used as a noun) of pendulus ‘hanging down’.