noun, often attributive
phos·​pho·​rus | \ ˈfäs-f(ə-)rəs How to pronounce phosphorus (audio) \

Definition of phosphorus

1 : a phosphorescent substance or body especially : one that shines or glows in the dark
2 or less commonly phosphorous \ ˈfäs-​f(ə-​)rəs How to pronounce phosphorous (audio) \ : a nonmetallic element of the nitrogen family with atomic number 15 that occurs widely in combination especially as phosphates, that is essential for life in all known organisms, and that is used especially in fertilizers and organophosphorus compounds — see Chemical Elements Table

Examples of phosphorus in a Sentence

Recent Examples on the Web About 65 percent of our bones are made of calcium and phosphorus, which also naturally circulate through our blood. Popular Science, "These trippy images reveal the colorful inner lives of bones," 4 Feb. 2020 Analysis showed that soils within the quarry are far more fertile than previously thought, with plenty of water and elevated levels of elements like calcium and phosphorus, which are essential in increasing crop yields. Jennifer Leman, Popular Mechanics, "The Real Meaning of the Statues on Easter Island," 16 Dec. 2019 Manure runoff contains nitrogen and phosphorus, which can drain into the Chesapeake Bay and cause harmful algal blooms. Carrie Arnold, National Geographic, "Veterinary drugs are wreaking havoc on wildlife worldwide," 6 Dec. 2019 This is the one time to apply a product with phosphorus, the middle number in an analysis, to make sure this nutrient is available for new root growth. Tom Maccubbin,, "Fertilize camellias when buds are present," 15 Nov. 2019 But in the longer-term, nutrients contained in the ash—such as phosphorus and nitrogen—could stimulate the growth of blue-green algae, which sometimes produce toxic chemicals. Mike Cherney, WSJ, "Australia Rain Forecast Brings Hope of Fire Relief—and Threat to Water Supply," 15 Jan. 2020 Chia seeds are good for bones As mentioned earlier, these mighty seeds pack several key nutrients tied to bone health, including calcium, magnesium, phosphorus, and manganese. Cynthia Sass, Mph,, "7 Chia Seed Benefits, According to a Nutritionist," 27 Aug. 2019 Harmful algal blooms develop each year in Lake Erie due to phosphorus in fertilizer and manure run-off in the Maumee River watershed. Mary Kilpatrick, cleveland, "2014, the year Cleveland lost Tamir Rice: Biggest stories of the 2010s," 21 Dec. 2019 Agriculture, leaking septic systems and municipal sewer plants add phosphorus into the water. USA TODAY, "Liberty State Park, Christmas Tree Lane, time capsule: News from around our 50 states," 3 Dec. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'phosphorus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of phosphorus

1680, in the meaning defined at sense 1

History and Etymology for phosphorus

New Latin, from Greek phōsphoros light-bearing — more at phosphor

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Time Traveler for phosphorus

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The first known use of phosphorus was in 1680

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Statistics for phosphorus

Last Updated

9 Feb 2020

Cite this Entry

“Phosphorus.” Dictionary, Merriam-Webster, Accessed 17 Feb. 2020.

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More Definitions for phosphorus


How to pronounce phosphorus (audio)

English Language Learners Definition of phosphorus

chemistry : a poisonous chemical element that glows in the dark and burns when it is touched by air


phos·​pho·​rus | \ ˈfäs-fə-rəs How to pronounce phosphorus (audio) \

Kids Definition of phosphorus

: a white or yellowish waxy chemical element that gives a faint glow in moist air


noun, often attributive
phos·​pho·​rus | \ ˈfäs-f(ə-)rəs How to pronounce phosphorus (audio) \

Medical Definition of phosphorus

: a nonmetallic multivalent element that occurs widely in combined form especially as inorganic phosphates in minerals, soils, natural waters, bones, and teeth and as organic phosphates in all living cells and that exists in several allotropic forms symbol P — see Chemical Elements Table

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More from Merriam-Webster on phosphorus

Spanish Central: Translation of phosphorus

Nglish: Translation of phosphorus for Spanish Speakers

Britannica English: Translation of phosphorus for Arabic Speakers Encyclopedia article about phosphorus

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