Term. n. A Christian supporting the Council of Nicaea's Trinitarian doctrine that Jesus, as Son of God, is consubstantial with God the Father. Pronunciation of Homoousion with 1 audio pronunciation and more for Homoousion. Homoousian definition is - an adherent of an ecclesiastical party of the fourth century holding to the doctrine of the Nicene Creed that the Son is of the same substance with the Father. A term first defined by the first general council of the Church to identify Christ's relationship to the Father. Homoousios synonyms, Homoousios pronunciation, Homoousios translation, English dictionary definition of Homoousios. HOMOOUSIOS. Pronunciation of homooúsios with 2 audio pronunciations, 1 meaning and more for homooúsios. How to say Homoousion in English? Definition. Homoousios is the Greek word meaning, “of one substance.” This Word was used to describe the relationship between Jesus and God at the Council of Nicaea at AD 325. How to say homooúsios in English? It is often used to contrast from the Arian view of the deity of Christ, which used the word homoiousios.