“Michelson-Morley”

We have one entry that includes the term Michelson-Morley.

Michelson-Morley experiment

noun

: an experiment that shows that the two parts of a divided ray of light travel at the same speed over paths perpendicular to each other (as over east-west and north-south paths) and that leads to the deductions that the motion of the earth through space has no effect upon the velocity of light and the absolute motion of the earth is not measurable

See the full definition

Word of the Day

Listen to the pronunciation of lackadaisical

See Definitions and Examples »

Test Your Vocabulary

Commonly Confused Words Quiz

  • vector image of a face with thought expression
  • I went to the ______ store to buy a birthday card.
Name That Thing

You know what it looks like… but what is it called?

TAKE THE QUIZ
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.

Pick the best words!

PLAY
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
image of a green cube out of place in a lineup of red spheres
Odd Word Out: Synonyms Vol. 2 Quiz Figure out which word isn't like the others.
See All