English

Alternative forms

• side-effect

Noun

side effect ‎(plural side effects)

1. (idiomatic) An unintended consequence of any action in addition to the intended consequence of that action.
   • 1987, Brundtland Report:

     The processing of certain raw materials - pulp and paper, oil, and alumina, for example - can have substantial environmental side effects.

   • 1980, Advanced Automation for Space Missions:

     A side effect of this architecture (which was designed only for efficient fabrication) is that it also performs automated repair.

   • 2007, Sylvia Escott-Stump, Nutrition and Diagnosis-Related Care:

     Useful for mild depression but may trigger coronary problems. A positive side effect is that it may actually help with degenerative joint disease symptoms.

2. (idiomatic, medicine) An adverse effect, an unintended consequence of a drug or therapy; usually not a beneficial effect.
3. (computing) A change in state caused by a function call (typically "side-effect").

   Eiffel is somewhat purist about insisting that functions have no side effects.

Usage notes

• Adjectives often applied to "side effect": mild, moderate, serious, severe, dangerous, unpleasant, debilitating, negative, positive, nasty, bad, horrible, terrible, painful, unexpected, unintended, strong, obvious, etc.

Synonyms

• by-product, untoward, unintentional

Translations