(Greek: of the same substance; like in substance)
Two words used attributively of Christ; the former by the Council of Nicaea (325) which declared that Christ was consubstantial and, consequently, coeternal and coequal with the Father, in order to offset the use of the latter by a sect of the Arians which maintained that Christ, although He was not a creature, was not of one and the same substance as the Father, that He had a beginning and was only like unto the Father.