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

Rather than treating it as waste, Aepnus feeds it into a modular electrolyzer that, when powered, drives electrochemical reactions to split and rearrange the ions into the original reagents – caustic soda and sulfuric acid. —Kapil Kajal, Interesting Engineering, 23 Sep. 2025

But direct air capture (DAC) systems consume a lot of energy and reagents that currently produce toxic by-products. —IEEE Spectrum, 15 Sep. 2025

So, get out the test tubes and reagents? —David Szondy august 27, New Atlas, 27 Aug. 2025

Stegra’s process uses renewable power to generate hydrogen, which is then used not as a fuel but as a chemical reagent. —Andrew Saunders, Fortune, 5 Aug. 2025

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

• newsagent
• subagent
• agent

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