(mathematical analysis, functional analysis, Fourier analysis) A quadratic functional which, given a real function defined on an open subset of ℝⁿ, yields a real number that is a measure of how variable said function is.

(energy efficiency) The energy that is lost due to standby electronic activity of equipment that is "off", on standby or sleep mode.

(cosmology, astrophysics, astronomy, physics) A category of dark energy, where dark energy is not fixed in amount nor in density, and continuously increases over time.

(informal) A device or appliance that uses electricity even while switched off. / (informal, derogatory) A person who is emotionally draining.

plural of energy vampire

A designated area for the generation of clean energy such as wind and solar power.

plural of energy park

(chemistry, physics) The amount of energy needed to slow down or stop a reaction.

An edible carbohydrate gel that provides energy for exercise and promotes recovery in endurance sports.

plural of energy gel