phosphorus
noun
phos·pho·rus
ˈfäs-f(ə-)rəs 
often attributive
1
: a phosphorescent substance or body
especially
: one that shines or glows in the dark
2
or less commonly phosphorous
: 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
Starter fertilizers supply phosphorus to help new lawns with root growth where permitted.
—
Tom MacCubbin, The Orlando Sentinel, 28 Mar. 2026
Meanwhile, Human Rights Watch has also accused Israel of using white phosphorus munitions over residential areas in southern Lebanon, a charge the Israeli military has denied.
—Chantal Da Silva, NBC news, 27 Mar. 2026
The processor was created by placing phosphorus atoms into silicon with atomic precision, allowing individual control of quantum bits.
—Neetika Walter, Interesting Engineering, 27 Mar. 2026
The safest fertilizers to apply are organic, low analysis (the three numbers representing nitrogen, phosphorus, and potassium are all single digits), or slow-release pellets.
—Joshua Siskin, Oc Register, 26 Mar. 2026
See All Example Sentences for phosphorus
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Tom MacCubbin, The Orlando Sentinel, 28 Mar. 2026
Meanwhile, Human Rights Watch has also accused Israel of using white phosphorus munitions over residential areas in southern Lebanon, a charge the Israeli military has denied.
—Chantal Da Silva, NBC news, 27 Mar. 2026
The processor was created by placing phosphorus atoms into silicon with atomic precision, allowing individual control of quantum bits.
—Neetika Walter, Interesting Engineering, 27 Mar. 2026
The safest fertilizers to apply are organic, low analysis (the three numbers representing nitrogen, phosphorus, and potassium are all single digits), or slow-release pellets.
—Joshua Siskin, Oc Register, 26 Mar. 2026
See All Example Sentences for phosphorus
Cite this Entry
“Phosphorus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/phosphorus. Accessed 5 Apr. 2026.
Copy CitationKids Definition
phosphorus
noun
phos·pho·rus
ˈfäs-f(ə-)rəs
1
: a phosphorescent substance
especially
: one that glows in the dark
2
: a nonmetallic element that occurs widely especially as phosphates see element
phosphoric
adjective
fäs-ˈfȯr-ik,
-ˈfär-
phosphorous
adjective
ˈfäs-f(ə-)rəs;
fäs-ˈfōr-əs,
-ˈfȯr-
Medical Definition
phosphorus
noun
phos·pho·rus
ˈfäs-f(ə-)rəs
often attributive
: 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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