Homoiousian

(Synop., § 130), n. [Gr. ὁμοιοῦσιος, ὁμοιούσιος, of like substance, from ὅμοιος, like, and οὐσία, the substance, being, essence, from εἶναι, to be, p. pr. ὤν, οὖσα, &c.] (Eccl. Hist.) One who held that the Son was of like, but not the same, essence with the Father.