“structure constant”

We have one entry that includes the term structure constant.

fine-structure constant

noun

: a dimensionless constant that is a measure of the strength of electromagnetic interactions of subatomic particles and that has an approximate value of 0.0073 or ¹/₁₃₇ —symbol α

See the full definition

Word of the Day

Listen to the pronunciation of jejune

See Definitions and Examples »

Test Your Vocabulary

Commonly Misspelled Words Vol. 2 Quiz

  • sequel spelled three ways with the incorrect ways crossed out and the correct spelling circled
  • Rachel seemed to be _____ in every endeavor she started.
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
book-magic-glow
Famous Novels, First Lines Quiz Can you identify these novels by their famous fir...
See All