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

Example Sentences

Recent Examples on the Web The phytochrome detects both red light and far-red light to establish circadian rhythms. Lydia Rivers, Discover Magazine, 20 July 2021 Nyctinastic plants know when to seal and unfurl thanks to phytochrome, a blue-green pigment associated with the absorption of light that helps regulate different types of growth and development. Lydia Rivers, Discover Magazine, 20 July 2021

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'phytochrome.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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.

First Known Use

1960, in the meaning defined above

Time Traveler
The first known use of phytochrome was in 1960

Dictionary Entries Near phytochrome

Cite this Entry

“Phytochrome.” Dictionary, Merriam-Webster, Accessed 1 Apr. 2023.

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