\Ho`mo*ou"si*an\, n. [Gr. ?; ? the same + ? being,
essence, substance.] (Eccl. Hist.)
One of those, in the 4th century, who accepted the Nicene
creed, and maintained that the Son had the same essence or
substance with the Father; -- opposed to homoiousian.

\Ho`mo*ou"si*an\, a.
Of or pertaining to the Homoousians, or to the doctrines they
held.