The technical notion of sensitive dependence on initial conditions in chaos theory.

(Britain) A secondary, often unintended effect; a repercussion, chain reaction.

plural of placebo effect

(physics) The visible scattering of light along the path of a beam caused by discontinuities such as suspended particles.

(physics) The tendency of alternating current to distribute itself in a conductor such that the current density is greater near the surface than near the core. The effect increases with frequency.

(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

(film, television) An effect that cannot be reasonably achieved by normal means, as for example by the digital manipulation of previously filmed footage.

(physics) The increase in the wavelength, and corresponding decrease in the energy, of photons (especially of X-rays and gamma rays) when scattered by interaction with matter

(pharmacology) The tendency of any medication or treatment, even an inert or ineffective one, to exhibit results simply because the recipient believes that it will work.