Ho`moi*ou"si*an (?), n. [Gr. &?;, &?;, 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.

Ho`moi*ou"si*an, a. Of or pertaining to Homoiousians, or their belief.