reactant

noun

re·​ac·​tant rē-ˈak-tənt How to pronounce reactant (audio)
: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
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 Like Pac-Man, this domain closes around reactants and reopens to release products. — Priyanka Naik, The Conversation, 7 Mar. 2025 The chemical processes are generally most efficient when there’s a constant supply of power and reactants. — Matthias Mueller, IEEE Spectrum, 19 Aug. 2023 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 See All Example Sentences for reactant

Word History

First Known Use

1916, in the meaning defined above

Time Traveler
The first known use of reactant was in 1916

Rhymes for reactant

See All Rhymes for reactant

Browse Nearby Words

reactance tube
reactant
reaction
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Cite this Entry

“Reactant.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/reactant. Accessed 7 Jul. 2026.

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Kids Definition

reactant

noun
re·​ac·​tant rē-ˈak-tənt How to pronounce reactant (audio)
: a substance that enters into and is changed by a chemical reaction

Medical Definition

reactant

noun
re·​ac·​tant -tənt How to pronounce reactant (audio)
: a substance that enters into and is altered in the course of a chemical reaction
reactant adjective

More from Merriam-Webster on reactant

Britannica.com: Encyclopedia article about reactant

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