(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.

(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

(quantum field theory) The effect of the Casimir force.

The state in which a series of repeated actions have an effect greater than the sum of their individual effects; noted especially in the repeated administration of drugs or repeated consumption of trace elements or chemicals that show no immediate effect.

To become enforceable, or applicable.

An accelerating growth of magnitude, including fame, fortune, importance, or danger.

The circumstance in which one event instigates an expansive set of other events.