side effect

noun

Definition of side effect

: a secondary and usually adverse effect (as of a drug) toxic side effects

called also side reaction

Examples of side effect in a Sentence

Nausea and diarrhea are the side effects of the drug. the harmful side effects of using chemicals to kill insects The merger created positive side effects for both companies.
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Recent Examples on the Web

Those principles were crafted to avoid missteps in developing new technology that could have harmful side effects. Douglas Macmillan, WSJ, "Microsoft Pushes Urgency of Regulating Facial-Recognition Technology," 6 Dec. 2018 Mood stabilizers may also cause more serious side effects. Korin Miller, SELF, "5 Bipolar Disorder Treatments You Should Know About," 30 Nov. 2018 Ebner found the treatment itself to be an easy process that only took a few minutes each day and had minimal side effects. The Seattle Times, "Protecting this mom’s heart from radiation," 15 Oct. 2018 The number of migrants going to Algeria may be increasing as an unintended side effect of Europe’s successful blocking of the Libyan crossing, said Camille Le Coz, an analyst at the Migration Policy Institute in Brussels. Lori Hinnant, The Seattle Times, "Algeria abandons thousands of migrants in Sahara," 25 June 2018 Michael Steinman, a professor of medicine at the University of California, San Francisco, pointed out that for many drugs, the risk of depression as a side effect is not well understood and may even be controversial. Carolyn Y. Johnson, Anchorage Daily News, "More than a third of American adults take prescription drugs that may increase risk of depression, study says," 13 June 2018 So has Americans’ reliance on prescription medications that list depression as a possible side effect. Karen Kaplan, latimes.com, "Are prescription medications making Americans depressed?," 12 June 2018 Michael Steinman, a professor of medicine at the University of California, San Francisco, pointed out that for many drugs, the risk of depression as a side effect is not well understood and may even be controversial. Carolyn Y. Johnson, chicagotribune.com, "More than a third of American adults take prescription drugs that may increase risk of depression, study says," 12 June 2018 Posting racist tweets is not listed as a possible side effect of taking the sleep drug Ambien. Tom Avril, Philly.com, "No, Ambien did not make Roseanne Barr a racist," 30 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'side effect.' 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 side effect

1814, in the meaning defined above

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Last Updated

14 Mar 2019

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The first known use of side effect was in 1814

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More Definitions for side effect

side effect

noun

English Language Learners Definition of side effect

: an often harmful and unwanted effect of a drug or chemical that occurs along with the desired effect
: a result of an action that is not expected or intended

side effect

noun

Medical Definition of side effect

: a secondary and usually adverse effect (as of a drug) toxic side effects a side effect of drowsiness caused by antihistamines

called also side reaction

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More from Merriam-Webster on side effect

Rhyming Dictionary: Words that rhyme with side effect

Spanish Central: Translation of side effect

Nglish: Translation of side effect for Spanish Speakers

Britannica English: Translation of side effect for Arabic Speakers

Britannica.com: Encyclopedia article about side effect

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