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 phosphorus (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 Nitrogen and phosphorus used to fertilize crops and lawns across the massive basin are washed into streams and rivers. John Sabo, Forbes, 17 June 2022 Nitrogen and phosphorus released from the plants is a significant contributor to many of the bay’s woes, not to mention the unsafe bacteria released along with them. Scott Dance, Baltimore Sun, 2 June 2022 For six of the 15 elements analyzed—aluminum, phosphorus, chlorine, potassium, copper, and zinc—the proportions were between 10 and 100 times higher than the ranges predicted by theoretical models. Jennifer Ouellette, Ars Technica, 2 June 2022 Most organic fertilizers contain nitrogen, phosphorus, potassium, or some combination of the three. Samantha Jones, Better Homes & Gardens, 10 May 2022 These tiny seeds are a good source of minerals like phosphorus, potassium, magnesium, and calcium. Marygrace Taylor, SELF, 30 Apr. 2022 Ukrainian officials have also alleged that separatist fighters from the Donetsk and Luhansk People’s Republic, as Russia refers to the areas, have also used white phosphorus--a highly flammable and deadly weapon. Washington Post, 1 Apr. 2022 The potent berry carries phytonutrients like carotenoids phenolics, anthocyanins, and flavonoids which help the body to resist fungi, bacteria and viral infections, and is high in vitamins A, B1, B2, niacin, albumin, iron, phosphorus, and calcium. Daphne Ewing-chow, Forbes, 31 Jan. 2022 This fertilizer will have little or no nitrogen but lots of phosphorus and potassium to promote flowering. Earl Nickel, San Francisco Chronicle, 1 Apr. 2022 See More

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.

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

Time Traveler

The first known use of phosphorus was in 1680

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Dictionary Entries Near phosphorus



phosphorus chloride

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Statistics for phosphorus

Last Updated

1 Jul 2022

Cite this Entry

“Phosphorus.” Dictionary, Merriam-Webster, Accessed 2 Jul. 2022.

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More Definitions for phosphorus


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

More from Merriam-Webster on phosphorus

Nglish: Translation of phosphorus for Spanish Speakers

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


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