“positron-emission”

We have one entry that includes the term positron-emission.

positron-emission tomography

noun

: tomography in which a cross-sectional image of regional metabolism is obtained by a usually color-coded representation of the distribution of gamma radiation given off in the collision of electrons in cells with positrons emitted by radionuclides incorporated into metabolic substances that have been administered (as by injection)

See the full definition

Word of the Day

Listen to the pronunciation of homage

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.
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

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.

You can make only 12 words. Pick the best ones!

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 Word Game You can make only 12 words. Pick the best ones!
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?
Missing Letter A crossword with a twist
winning words from the national spelling bee logo
Spelling Bee Quiz Can you outdo past winners of the National Spelli...