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
The material, left over from when the moon’s magma ocean solidified, is a combination of potassium, rare Earth elements and phosphorus found in lunar rocks.
—
Ashley Strickland, CNN Money, 21 Feb. 2026
Goat yogurt is higher in minerals than cow yogurt, and is an excellent source of magnesium, phosphorus, and calcium.
—Alessandra Signorelli, Vogue, 21 Feb. 2026
Micronutrients are another benefit, as oats naturally contain iron, magnesium, phosphorus and B vitamins, which are important for metabolism, nerve function and overall cellular health.
—Daryl Austin, USA Today, 21 Feb. 2026
Leafy vegetables, for example, require more nitrogen, whereas root vegetables such as carrots need more phosphorus.
—Nadia Hassani, The Spruce, 20 Feb. 2026
See All Example Sentences for phosphorus
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Ashley Strickland, CNN Money, 21 Feb. 2026
Goat yogurt is higher in minerals than cow yogurt, and is an excellent source of magnesium, phosphorus, and calcium.
—Alessandra Signorelli, Vogue, 21 Feb. 2026
Micronutrients are another benefit, as oats naturally contain iron, magnesium, phosphorus and B vitamins, which are important for metabolism, nerve function and overall cellular health.
—Daryl Austin, USA Today, 21 Feb. 2026
Leafy vegetables, for example, require more nitrogen, whereas root vegetables such as carrots need more phosphorus.
—Nadia Hassani, The Spruce, 20 Feb. 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 26 Feb. 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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