phy·​to·​chrome | \ ˈfī-tə-ˌkrōm How to pronounce phytochrome (audio) \

Definition of phytochrome

: any of a group of proteins bound to light-absorbing pigments in many plants that play a role in initiating floral and developmental processes when activated by red or near-infrared radiation

First Known Use of phytochrome

1960, in the meaning defined above

History and Etymology for phytochrome

phyto- + -chrome

Note: The term phytochrome was introduced by the American botanist Harry A. Borthwick (1898-1974) and the biochemist Sterling B. Hendricks (1902-81) in 1960, apparently first in an article coauthored with S. Nakayama, "Failure of photoreversible control of flowering in Pharbitis nil," Botanical Gazette, vol. 121, no. 4 (June, 1960), p. 242, and more formally in the article "Photoperiodism in plants," Science, vol. 132, issue 3435 (October 28, 1960), pp. 1223-28.

Keep scrolling for more

Learn More about phytochrome

Time Traveler for phytochrome

Time Traveler

The first known use of phytochrome was in 1960

See more words from the same year

Statistics for phytochrome

Cite this Entry

“Phytochrome.” Dictionary, Merriam-Webster, Accessed 23 Oct. 2020.

More from Merriam-Webster on phytochrome Encyclopedia article about phytochrome

Comments on phytochrome

What made you want to look up phytochrome? Please tell us where you read or heard it (including the quote, if possible).


Test Your Vocabulary

Farm Idioms Quiz

  • cow coming home
  • What does 'poke' refer to in the expression 'pig in a poke'?
Spell It

Can you spell these 10 commonly misspelled words?

Dictionary Devil

Test Your Knowledge - and learn some interesting things along the way.

Love words? Need even more definitions?

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