The Britannica Dictionary
mobile search
Home
Ask the Editor
Word of the Day
Quizzes
Core Vocabulary
Browse the Dictionary
×
Britannica Homepage
Ask the Editor
Word of the Day
Quizzes
Core Vocabulary
Browse the Dictionary
The Britannica Dictionary
atomic clock
1 ENTRIES FOUND:
atomic clock
(noun)
atomic clock
noun
plural
atomic clocks
atomic clock
noun
plural
atomic clocks
Britannica Dictionary definition of ATOMIC CLOCK
[
count
]
:
a special kind of clock that is extremely exact
ASK THE EDITOR
Why do we say "did you know" rather than "do you know"?
See the answer »
QUIZZES
Vocabulary Quiz
Test your word power
Take the Quiz »
Name That Thing
Take our visual quiz
Test Your Knowledge »
WORD OF THE DAY
protocol
:
a system of rules that explain the correct conduct and procedures to follow in formal situations
Learn More »