Eating Disorder Not Otherwise Specified — EDNOS — was the diagnostic home for eating disorders that fell short of the full criteria for anorexia nervosa, bulimia nervosa, or binge-eating disorder. A patient might show all the behaviours and distress of bulimia but binge less often than the threshold requires, or all the features of anorexia without the low-weight cutoff. The label was never meant to mean “mild” — EDNOS presentations carry the same medical risks and mortality as the full diagnoses — but the residual category proved so common that it exposed the limits of rigid criteria. Later diagnostic manuals reworked the system, moving many EDNOS cases into named diagnoses like “other specified feeding or eating disorder.” The history of EDNOS is a lesson in classification: real patients rarely read the textbook before getting ill.