Homoiousian

n. [ Gr. &unr_;, &unr_;, of like substance; "o`moios + o'ysi`a the substance, being, essence.] (Eccl. Hist.) One of the semi-Arians of the 4th century, who held that the Son was of like, but not the same, essence or substance with the Father; -- opposed to homoousian. [1913 Webster]