homoiousian

noun

ho·​moi·​ou·​si·​an hō-ˌmȯi-ˈü-zē-ən 

hä-,

-ˈü-sē-

: an adherent of an ecclesiastical party of the fourth century holding that the Son is essentially like the Father but not of the same substance

Word History

Etymology

Late Greek homoiousios of like substance, from Greek homoi- homeo- + ousia essence, substance, from ont-, ōn, present participle of einai to be — more at is

First Known Use

1732, in the meaning defined above