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phosphorous

American  
[fos-fer-uhs, fos-fawr-uhs, -fohr-] / ˈfɒs fər əs, fɒsˈfɔr əs, -ˈfoʊr- /

adjective

Chemistry.
  1. containing trivalent phosphorus.


phosphorous British  
/ ˈfɒsfərəs /

adjective

  1. of or containing phosphorus in the trivalent state

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of phosphorous

First recorded in 1770–80; phosphor- + -ous

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

In healthy soils, these fungal networks can expand the effective foraging area of plant roots by up to 100 times and provide > 80 percent of a plant's phosphorous needs.

From Science Daily • Jun. 15, 2026

The report from environment groups Size of Wales and WWF Cymru says the soy is high in phosphorous, and becomes a pollutant when animal manure spread on land runs off into rivers.

From BBC • Nov. 9, 2025

Molasses is naturally rich in antioxidants, iron, calcium, magnesium, potassium, phosphorous and vitamin B6.

From Salon • Dec. 12, 2023

White phosphorous is considered an incendiary weapon under Protocol III of the Convention on the Prohibition of Use of Certain Conventional Weapons.

From Reuters • Oct. 12, 2023

Leah told Willets that perhaps spirits could materialize phosphorous, the way they apported flowers and doves.

From "American Spirits" by Barb Rosenstock

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