The story
From Ancient Greek ὁμοούσιος (homooúsios) + -an, from ὁμός (homós, “same”) + οὐσία (ousía, “essence”).
Etymology from Wiktionary, CC BY-SA 4.0.
homoousian
Today it means: Having the same essence or substance, especially with reference to the first and second persons of the Trinity (Father and Son). Full definition →