side effect

or side-ef·fect

See synonyms for: side effectside effects on

  1. any effect of a drug, chemical, or other medicine that is in addition to its intended effect, especially an effect that is harmful or unpleasant.

  2. any accompanying or consequential and usually detrimental effect: the side effects of air pollution.

Origin of side effect

First recorded in 1880–85

Words Nearby side effect Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use side effect in a sentence

British Dictionary definitions for side effect

side effect

  1. any unwanted nontherapeutic effect caused by a drug: Compare aftereffect (def. 2)

  2. any secondary effect, esp an undesirable one

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012