(1) A subsidence of symptoms. (2) A relapse; a return of symptoms. (3) Any retrograde movement or action. (4) A return to a more primitive mode of behavior due to an inability to function adequately at a more adult level. (5) An unconscious defense mechanism by which there occurs a return to earlier patterns of adaptation. (6) The distribution of one random variable given particular values of other variables relevant to it (e.g., a formula for the distribution of weight as a function of height and chest circumference). The method was formulated by Galton in his study of quantitative genetics. [L. regredior, pp. -gressus, to go back]