consubstantialis, translating Greek ὁμοούσιος
Consubstantial
kon-sub-STAN-shul
The word the Council of Nicaea (325) chose to say that the Son is fully God, “of the same substance” as the Father; said every Sunday in the Creed.
of the same substance
When Arius taught that the Son was a creature, exalted but not eternal, the Council of Nicaea answered with a single Greek word: homoousios, “of one substance with the Father,” rendered in Latin as consubstantialis. It means the Son is not like God or made by God but is everything the Father is, God from God, light from light. The 2011 English translation of the Creed restored “consubstantial” in place of “one in Being” to keep the precision of the original. The Catechism also confesses the Holy Spirit as consubstantial with the Father and the Son.
Not to be confused with Transubstantiation.
Councils
Where the Church settled or debated this. Follow a council to read our article on it, or the decrees themselves.
- 325First Council of Nicaeaour article
- 381First Council of Constantinopleour article
Sources checked 29 September 2026