phosphoric acid

noun

1

: a syrupy or deliquescent tribasic acid H₃PO₄ used especially in preparing phosphates (as for fertilizers), in rust-proofing metals, and especially formerly as a flavoring in soft drinks

called also orthophosphoric acid

2

: a compound (such as pyrophosphoric acid or metaphosphoric acid) consisting of phosphate groups linked directly to each other by oxygen

Examples of phosphoric acid in a Sentence

Recent Examples on the Web

Its state railway has ordered 780 railcars from US manufacturer Greenbrier, including tank cars for phosphoric acid and molten sulfur. — semafor.com, 24 Sep. 2026

Some research indicates that artificial sweeteners and phosphoric acid can strain the kidneys, raising the risk of damage. — Cristina Mutchler, Verywell Health, 3 June 2026

Fifty-eight pounds of phosphoric acid, natural oils and 12 gallons each of caramel and lime juice combined with water, alcohol and sugar. — Ryan Wilusz, USA Today, 15 Apr. 2026

Foods and drinks high in fiber, phytic acid, phosphoric acid, alcohol, and caffeine can interfere with how well your body uses magnesium. — Jillian Kubala, Health, 3 Nov. 2025

Word History

First Known Use

1765, in the meaning defined at sense 1

Rhymes for phosphoric acid

• antacid
• placid

Kids Definition

phosphoric acid

noun

phos·​phor·​ic acid

fäs-ˌfȯr-ik-, 

-ˌfär-

: any of several oxygen-containing acids of phosphorus

Medical Definition

phosphoric acid

noun

1

: a syrupy or deliquescent tribasic acid H₃PO₄ used especially in preparing phosphates (as for fertilizers), in rust-proofing metals, and especially formerly as a flavoring in soft drinks

called also orthophosphoric acid

2

: a compound (as pyrophosphoric acid or metaphosphoric acid) consisting of phosphate groups linked directly to each other by oxygen