A unit of measure for rate of change of acceleration with distance i.e., the gradient of acceleration. It has magnitude and dimensions 10^-9 m/(s²m) or 10^-9 cm/(s²cm). The quantity is sometimes given as 10^-9 s^-2. This form is dimensionally correct but physically wrong and should not be used. The Eötvös unit is used principally in expressing values of gravity gradient. Gravity gradiometers typically have sensitivities of 0. 1 to 1. 0 Eötvös units. E. U. and E have been used as symbols for the unit; the former is preferred.