1. (Also known as the universal equilibrium range. ) The range of higher-frequency eddies in the turbulence kinetic energy spectrum within which the energy cascade takes place. The equilibrium range includes the inertial subrange and lies between the range of energy- containing eddies and the viscous subrange. 2. That part of the ocean wave spectrum where a balance exists among the input of energy from the wind, the transfer of energy to different wave components (nonlinear wave–wave interactions) and the dissipation of energy due to breaking.