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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.

See Examples For:

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 microbes multiply as they consume the hydrogen, the carbon dioxide, and a few additional nutrients, such as calcium and phosphorous.

From Salon Jan. 29, 2025

Fertilisers – like chicken manure - add additional nutrients like phosphorous and nitrogen to rivers.

From BBC May 24, 2024

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

Milkman’s left foot hovered above the floor, and Guitar’s eyes with their phosphorous lights singed his heart a little, but he took the stare.

From "Song of Solomon" by Toni Morrison

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