re·​ac·​tiv·​i·​ty | \ (ˌ)rē-ˌak-ˈti-və-tē How to pronounce reactivity (audio) \

Definition of reactivity

: the quality or state of being reactive emotional reactivity chemical reactivity If the brain, responding to psychological stress, stimulates the release of cortisol and cortisol suppresses the reactivity of the immune system, then a dormant viral infection may well flare up, or a new one catch hold.— Matt Ridley Abnormal reactivity to light and abnormal pupillary size may be important clues to the presence of cranial injury in the setting of head trauma.— Bradford J. Shingleton

Examples of reactivity in a Sentence

Recent Examples on the Web And this is where mindfulness training exercises, which are about paying attention to present moment experience without elaboration or reactivity, are so key. Kathy Caprino, Forbes, 26 Oct. 2021 Powered by advanced propellant technology that is VOC exempt, its compounds have low photochemical reactivity. Joseph Deacetis, Forbes, 2 Nov. 2021 At one extreme is our normal automatic reactivity and at the opposite extreme is insightful proactivity. Ron N Hurst, Forbes, 22 Oct. 2021 When this happens, emotional reactivity loses its charge because the right and left parts of the brain become more connected, says psychiatrist and author Dr. Dan Siegel in his book Mindsight. Time, 28 Oct. 2021 Engage with tenants ahead of problems; proactivity is always cheaper than reactivity especially in light of labor and supply challenges. Forbes Biz Council Expert Panel, Forbes, 20 Oct. 2021 Scientists have also made considerable advances in the development of nanostructured fusion fuel, which greatly increases the absorption of laser energy and thus enhances fusion reactivity. Moritz Von Der Linden, Forbes, 7 Sep. 2021 Emotional reactivity can get the best of you at the moment. Tarot Astrologers,, 30 Aug. 2021 De Erausquin’s team assessed the patients three to six months after they were infected with the coronavirus, measuring factors such as cognitive abilities, emotional reactivity, motor function and coordination. Washington Post, 12 Feb. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'reactivity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of reactivity

1832, in the meaning defined above

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Time Traveler for reactivity

Time Traveler

The first known use of reactivity was in 1832

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Dictionary Entries Near reactivity

reactive volt-amperes



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Statistics for reactivity

Last Updated

1 Jan 2022

Cite this Entry

“Reactivity.” Dictionary, Merriam-Webster, Accessed 19 Jan. 2022.

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More Definitions for reactivity


re·​ac·​tiv·​i·​ty | \ (ˌ)rē-ˌak-ˈtiv-ət-ē How to pronounce reactivity (audio) \
plural reactivities

Medical Definition of reactivity

: the quality or state of being reactive skin reactivity emotional reactivity


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