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Definition of “side effect” - English Dictionary

"side effect" in American English

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side effectnoun [C usually pl]

 us   /ˈsɑɪd ɪˌfekt/
an ​unwanted or ​unexpectedresult or ​condition that comes along with the ​desired effects of something: Does this ​drug have any side effects?
(Definition of side effect from the Cambridge Academic Content Dictionary © Cambridge University Press)

"side effect" in British English

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side effectnoun [C]

uk   /ˈsaɪd ɪˌfekt/  us   /ˈsaɪd ɪˌfekt/
C1 an ​unpleasanteffect of a ​drug that ​happens in ​addition to the ​maineffect: Does this ​drug have any ​sideeffects?
C2 an ​unexpectedresult of a ​situation: A ​sideeffect of the new ​law is that fewer ​people will take out ​insurance.

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(Definition of side effect from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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