atomic clock

noun
  1. an extremely accurate electronic clock regulated by the resonance frequency of atoms or molecules of certain substances, as cesium.

Origin of atomic clock

First recorded in 1935–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for atomic clock

atomic clock

noun
  1. an extremely accurate clock in which an electrical oscillator is controlled by the natural vibrations of an atomic or molecular system such as caesium or ammonia
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

atomic clock in Science

atomic clock

  1. An extremely precise clock whose rate is controlled by a periodic process (such as vibration, or the absorption or emission of electromagnetic radiation) that occurs at a steady rate in atoms or molecules. The standard atomic clock is based on the vibrations of cesium atoms and is so accurate that it would gain or lose less than one second in three million years. Atomic clocks are used to help track satellites, run navigation systems, and study movements of the Earth's crust.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

atomic clock in Culture

atomic clock

The most accurate clock available. Time is measured by the movement of electrons in cesium atoms. The standard second is now defined by measurements on an atomic clock.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.