phosphate

noun

phos·​phate ˈfäs-ˌfāt 

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

Fluoride is an element that strengthens tooth enamel, in part by bonding with phosphate and calcium in teeth to fight the process that causes cavities to form — and its addition to drinking water and toothpaste has slashed tooth decay in the U.S. —Saul Elbein, The Hill, 1 May 2025

Located in the heart of downtown Apalachicola on Market Street, Old Time Soda Fountain delivers the perfect classic 1950s soda fountain vibes alongside a huge selection of ice cream, shakes, floats, phosphates, and other old-school treats. —Tara Massouleh McCay, Southern Living, 27 Apr. 2025

Similar chemicals found in Mars dust have also been identified in coal dust, which the Interagency for Research on Cancer reports to include silica, phosphates, and arsenic, among others. —Madison Dapcevich, Discover Magazine, 25 Apr. 2025

The most prominent candidates are potassium and phosphate, both of which increase during exercise and are associated in some studies with muscle fatigue. —Alex Hutchinson, Outside Online, 24 Apr. 2025

Word History

Etymology

French, from acide phosphorique phosphoric acid

First Known Use

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

Phrases Containing phosphate

• ammonium phosphate
• calcium phosphate
• creatine phosphate
• diammonium phosphate
• disodium phosphate
• glucose phosphate
• glucose-6-phosphate dehydrogenase
• nicotinamide adenine dinucleotide phosphate
• phosphate rock
• trisodium phosphate

Rhymes for phosphate

• bisphosphate
• diphosphate
• triphosphate
• glycerophosphate
• organophosphate
• metaphosphate
• monophosphate
• orthophosphate
• polyphosphate
• pyrophosphate
• superphosphate

Kids Definition

phosphate

noun

phos·​phate ˈfäs-ˌfāt 

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 

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)