photoreaction

noun

pho·​to·​re·​ac·​tion ˌfō-tō-rē-ˈak-shən How to pronounce photoreaction (audio)
: a photochemical reaction

Word History

First Known Use

1909, in the meaning defined above

Time Traveler
The first known use of photoreaction was in 1909

Dictionary Entries Near photoreaction

photoradiography

photoreaction

photoreactivation

See More Nearby Entries 

Cite this Entry

“Photoreaction.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/photoreaction. Accessed 16 Nov. 2024.

Copy Citation

Share

Medical Definition

photoreaction

noun
pho·​to·​re·​ac·​tion -rē-ˈak-shən How to pronounce photoreaction (audio)
: a photochemical reaction
Love words? Need even more definitions?

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

Popular in Grammar & Usage

See All

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Plural and Possessive Names: A Guide

The Difference Between 'i.e.' and 'e.g.'

Why is '-ed' sometimes pronounced at the end of a word?

What's the difference between 'fascism' and 'socialism'?
See All

Popular in Wordplay

See All

8 Words with Fascinating Histories

8 Words for Lesser-Known Musical Instruments

Birds Say the Darndest Things

10 Words from Taylor Swift Songs (Merriam's Version)

10 Scrabble Words Without Any Vowels
See All

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 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?
Missing Letter A daily crossword with a twist
silhouette of a man with a megaphone against a british flag
Another Great British Vocabulary Quiz, Innit? A double-decker quiz with words from across the pond