reagent

noun

re·​agent rē-ˈā-jənt 

: a substance used (as in detecting or measuring a component, in preparing a product, or in developing photographs) because of its chemical or biological activity

Examples of reagent in a Sentence

Recent Examples on the Web

Investigators used a latent bloodstain reagent and found that blood had been cleaned up from inside and outside the home, according to the affidavit. — Annasofia Scheve, San Antonio Express-News, 13 Apr. 2026

There were beakers everywhere, full of chemical reagents such as sodium hydrosulfite and inorganic bases. — Clayton Dalton, New Yorker, 13 Mar. 2026

Chiang’s team used a liquid reagent made of water and ammonium fluoride — the active chemical in glass etchant — to do the exact opposite. — Mrigakshi Dixit, Interesting Engineering, 28 May 2026

Radiological weapons can be detected by a Geiger counter, while chemical weapons can usually be identified by reagents, electronic sensors, and special detection sheets sensitive to things like nerve agents. — David Szondy june 27, New Atlas, 27 June 2026

Word History

Etymology

New Latin reagent-, reagens, present participle of reagere to react — more at react

First Known Use

1797, in the meaning defined above

Phrases Containing reagent

• Schiff reagent
• Schiff's reagent

Rhymes for reagent

• agent
• newsagent
• subagent

Medical Definition

reagent

noun

re·​agent rē-ˈā-jənt 

1

: a substance used (as in detecting or measuring a component, in preparing a product, or in developing photographs) because of its chemical or biological activity

2

: reactor sense 1b