Definitions for "Energy Density"
The amount of energy a cell can contain. The energy density is referred to the ratio of cell energy to weight or volume.
is the amount of energy stored in a given system or region of space per unit volume, and is most commonly denoted u. It therefore has units of energy per length cubed.
The amount of energy a cell can contain. Gravimetric energy is the Watt-hours a battery is capable of providing per given weight (pound or Kg); and volumetric energy is the Watt-hours per given size (cubic inch or cubic centimeter). The energy is defined as nominal battery voltage multiplied by rated capacity.
Keywords:  macroscopic, system
Macroscopic system
The amount of energy contained in a given quantity of food
Simply the amount of energy available in a specific quantity of propellant.