reactant

noun

re·​ac·​tant rē-ˈak-tənt 

: a substance that enters into and is altered in the course of a chemical reaction

Examples of reactant in a Sentence

Recent Examples on the Web

During many chemical reactions, the initial set of molecules, called reactants, have to overcome an energy barrier as their atoms are rearranged into the products of the reaction. — Sophya Garashchuk, The Conversation, 1 Oct. 2026

The system features an open architecture that pairs a pure lithium metal negative electrode directly with ambient oxygen drawn from the surrounding atmosphere to act as the positive electrode reactant. — Aman Tripathi, Interesting Engineering, 3 June 2026

One of the most elegant features of the beetle’s anatomy is that the reactants aren’t stored in a mixed state. — Scott Travers, Forbes.com, 21 Apr. 2026

The compartments formed by a matrix and a membrane crucially provide a stable environment that can concentrate reactants and protect them from the external environment, allowing the necessary chemical reactions to take place. — Discover Magazine, 17 Oct. 2024

Word History

First Known Use

1916, in the meaning defined above

Rhymes for reactant

• attractant
• extractant
• surfactant

Kids Definition

reactant

noun

re·​ac·​tant rē-ˈak-tənt 

: a substance that enters into and is changed by a chemical reaction

Medical Definition

reactant

noun

re·​ac·​tant -tənt 

: a substance that enters into and is altered in the course of a chemical reaction

reactant adjective