Wikipedia
Homoousion ( ; , from , homós, "same" and , ousía, "being") is a Christian theological doctrine pertaining to the Trinitarian understanding of God. The Nicene Creed describes Jesus as being with God the Father, i.e. Jesus is "one in being" with the Father. The term was adopted at the First Council of Nicaea to clarify the nature of the relationship between Christ and God the Father within the Godhead. In Latin, and in Romance languages that lack a present participle of the verb be, the term is rendered consubstantialis or a translation thereof. It is one of the cornerstones of theology in Nicene Christianity.
Usage examples of "homoousion".
I see that the men who killed each other about the orthodoxy of the Homoousion were far more sensible than the people who are quarrelling about the Education Act.
A letter was publicly read, and ignominiously torn, in which their patron, Eusebius of Nicomedia, ingenuously confessed, that the admission of the Homoousion, or Consubstantial, a word already familiar to the Platonists, was incompatible with the principles of their theological system.
The Homoousion is rejected, and received, and explained away by successive synods.
One question, which gradually arose from the Arian controversy, may, however, be noticed, as it served to produce and discriminate the three sects, who were united only by their common aversion to the Homoousion of the Nicene synod.
Arian pestilence approached their frontiers, they were supplied with the seasonable preservative of the Homoousion, by the paternal care of the Roman pontiff.
Roman empire was successively witness to his merit, and his sufferings in the cause of the Homoousion, which he considered as the sole pleasure and business, as the duty, and as the glory of his life.