(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.

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

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

(physics) The energy of a heterogeneous (polychromatic) photon beam calculated as if it were monochromatic

The property of being cost-effective.

Returning a benefit that justifies the initial investment; economical.

plural of placebo effect

(medicine) The lowest pharmaceutical dosage required to cause effect in 50% of average individuals.

(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