atomic clock

noun

: a precision clock that depends for its operation on an electrical oscillator regulated by the natural vibration frequencies of an atomic system (such as a beam of cesium atoms)

Examples of atomic clock in a Sentence

Recent Examples on the Web
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Last year, on July 5, 2024, Earth experienced the shortest day ever recorded since the advent of the atomic clock 65 years ago, at 1.66 milliseconds less than 24 hours. Jacopo Prisco, CNN Money, 21 July 2025 From when records began (with the invention of the atomic clock) in 1973 until 2020, the shortest day ever recorded was 1.05 milliseconds less than 24 hours, according to Timeanddate.com. Jamie Carter, Space.com, 21 July 2025 This particular clock is technically an ion clock, which is different from the more common atomic clocks that are based on measuring the resonant frequencies of a single cesium atom to regulate time keeping. New Atlas, 18 July 2025 The shortest day ever recorded since atomic clocks went into operation in the 1950s occurred last year, on July 5, according to Date and Time, when the Earth shaved off 1.66 milliseconds. Jeffrey Kluger, Time, 9 July 2025 See All Example Sentences for atomic clock

Word History

First Known Use

1924, in the meaning defined above

Time Traveler
The first known use of atomic clock was in 1924

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Cite this Entry

“Atomic clock.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/atomic%20clock. Accessed 25 Jul. 2025.

Kids Definition

atomic clock

noun
: an extremely exact clock that depends for its operation on the natural vibrations of atoms (as of cesium)

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