Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Medical
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

atomic clock

noun

Simple Definition of atomic clock

  • : a special kind of clock that is extremely exact

Full Definition of atomic clock

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

1938

First Known Use of atomic clock

1938


Learn More about atomic clock


Seen and Heard

What made you want to look up atomic clock? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

February 6, 2016

an official order, decree, or edict

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

image1037863653

Which of the following refers to thin, bending ice, or to the act of running over such ice?

kittly-benders pince-nez duvet spindrift
Name That Thing

10 quick questions: hear them, spell them, and see how your skills compare to the crowd.

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ