Energy consumption per physical unit of output (also called physical energy intensity).

the amount of energy available for a sustained period of time divided by the weight of the battery.

The energy contained in a stream of water, expressed in terms of head, referred to the bed of a stream. It is equal to the mean depth of water plus the velocity head of the mean velocity.

The ratio of the energy output of a cell or battery to its weight (Wh/kg). This term is used interchangeably with gravimetric energy density.

A battery's rated energy per unit weight. Measured in units of watt-hours per kilogram (Wh/kg).

Specific energy is defined as the energy per unit mass. It is an intensive property. Contrast this with energy, which is an extensive property.