Ho·moi·ou·si·an (hō′moi-sē-ən, -zē-)
An adherent of the Christian doctrine, formulated in the fourth century AD, that Jesus the Son and God the Father are of similar but not of the same substance.
[From Greek homoiousios, of similar substance : homoio-, homeo- + ousiā, substance (from ousa, feminine present participle of einai, to be; see es- in the Appendix of Indo-European roots).]
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