side effect


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

Billi’s identity crisis comes into view as the side effect of a larger and graver situation. New York Times, "Review: In ‘The Farewell,’ a Sham Wedding Is Really a Premature Funeral," 11 July 2019 But Facebook's policies prohibit the sale of prescription drugs, and the FDA requires companies to list the side effects in ads, which these do not. Alex Baker-whitcomb, WIRED, "Microsoft’s eBook Apocalypse, Facebook Drug Ads, and More News," 1 July 2019 Ethicists also have raised concerns about the lack of full and free consent and the potential side effects of involuntary castration, including a higher risk of osteoporosis. The Washington Post, The Denver Post, "Alabama governor signs “chemical castration” bill for some sex offenders," 11 June 2019 Drug companies frequently have been pilloried for not fully disclosing negative side effects of their drugs. Author: Christopher Rowland, Anchorage Daily News, "Pfizer had clues its blockbuster drug could prevent Alzheimer’s. Why didn’t it tell the world?," 5 June 2019 But one small detail in particular stands out, a side effect of the split: After two years, Destiny 2 is coming to Steam. Hayden Dingman, PCWorld, "Destiny 2 is coming to Steam and going free-to-play in September," 6 June 2019 But a four-day hospital stay stretched into 10 weeks as Millie’s lungs healed and doctors attended to two blood clots that formed in her heart, a side effect of ECMO. Shari Rudavsky, Indianapolis Star, "The machine that saved Millie — and 999 other Riley kids before her," 6 June 2019 Certain medications, like some antidepressants, may also have nightmares as a side effect. Cassie Shortsleeve, SELF, "9 Types of Parasomnias That Might Explain That Weird Thing You Do When You Sleep," 5 June 2019 Bright/loud signatures that are unambiguous and packed with info are ideal, and the quest for them should, as a side effect, produce scientific results other fields can use. Sarah Scoles, WIRED, "The WIRED Guide to Aliens," 5 June 2019

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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Statistics for side effect

Last Updated

18 Jul 2019

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Time Traveler for side effect

The first known use of side effect was in 1814

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More Definitions for side effect

side effect


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


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 Encyclopedia article about side effect

Comments on side effect

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