Of the three standard turbulence length scales, the ones that are measures of the largest separation distance over which components of the eddy velocities at two distinct points are correlated. They characterize the energy-containing range of eddy length scales. In the most general form, the integral scales (expressed here as a tensor) are functions of position and are defined in terms of the normalized two-point velocity correlations. Compare Taylor microscale, Kolmogorov microscale.