Ed5/4 means Division of the Just Major Third (5/4) into n equal parts.
Division of the just major third into n equal parts
Division of the 5:4 into equal parts can be conceived of as to directly use this interval as an equivalence, or not. The question of equivalence is still in its infancy. The utility of 5:4 as a base though, is apparent by providing a novel consonance after 3, and being the basis for 5-limit harmony. Many, if not all, of these scales have a perceptually important pseudo (false) octave, with various degrees of accuracy.