phosphate

noun

phos·​phate ˈfäs-ˌfāt How to pronounce phosphate (audio)
1
a(1)
: a salt or ester of a phosphoric acid
(2)
: the trivalent anion PO43− derived from phosphoric acid H3PO4
b
: an organic compound of phosphoric acid in which the acid group is bound to nitrogen or a carboxyl group in a way that permits useful energy to be released (as in metabolism)
2
: an effervescent drink of carbonated water with a small amount of phosphoric acid flavored with fruit syrup
3
: a phosphatic material used for fertilizers

Examples of phosphate in a Sentence

Recent Examples on the Web
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The phosphate and fertilizer producer fell 5% after its first-quarter earnings disappointed. Davis Giangiulio, CNBC, 11 May 2026 Inside, the formula combines four forms of vitamin C—ascorbyl glucoside, ascorbic acid, 3-O-ethyl ascorbic acid, and sodium ascorbyl phosphate—for a more layered, stable approach to brightening and antioxidant protection. Christa Joanna Lee, Allure, 9 May 2026 Its original 1886 owner, Francis Silas Rodgers, had money—and lots of it—from cotton brokering, phosphates, and shipping. Condé Nast, Condé Nast Traveler, 7 May 2026 Sodium still lags slightly behind lithium iron phosphate (LFP), the dominant chemistry in the global EV market, on energy density. Omar Kardoudi april 28, New Atlas, 28 Apr. 2026 See All Example Sentences for phosphate

Word History

Etymology

French, from acide phosphorique phosphoric acid

First Known Use

1788, in the meaning defined at sense 1a(1)

Time Traveler
The first known use of phosphate was in 1788

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Cite this Entry

“Phosphate.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/phosphate. Accessed 16 May. 2026.

Kids Definition

phosphate

noun
phos·​phate ˈfäs-ˌfāt How to pronounce phosphate (audio)
1
: a salt of a phosphoric acid
2
: a drink made of carbonated water and fruit syrup with a little phosphoric acid added for tang

Medical Definition

phosphate

noun
phos·​phate ˈfäs-ˌfāt How to pronounce phosphate (audio)
1
a
: a salt or ester of a phosphoric acid
b
: the trivalent anion PO43− derived from phosphoric acid H3PO4
2
: an organic compound of phosphoric acid in which the acid group is bound to nitrogen or a carboxyl group in a way that permits useful energy to be released (as in metabolism)

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