(voting theory) the effect a minor party candidate with little chance of winning has upon a close election, when that candidate's presence in the election draws votes from a candidate similar to them, thereby causing a candidate dissimilar to them to win the election.

(chemistry) the mesomeric effect

(chemistry) the increased stability of organic compounds having alternate single and double bonds

(chemistry, physics) The characteristic change in optical rotatory dispersion and/or circular dichroism in the vicinity of an absorption band of a substance.

Alternative spelling of side effect

To alter as a side effect.

An unintended consequence of any action in addition to the intended consequence of that action.

The apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves.

(physics) an effect that arises from the relation between the angular momentum and the magnetization of a magnetic substance

(physics) the effect in which a conductor that carries an electric current perpendicular to an applied magnetic field develops a voltage gradient transverse to both current and field