Definition of Marcionitism in English:
Marcionitism
noun ˈmɑːʃ(ɪ)ənɪˌtɪz(ə)mˈmɑːsɪənɪˌtɪz(ə)m
Church History The doctrines of the Marcionites.
Origin
Late 19th century; earliest use found in Encyclopaedia Britannica. From Marcionite adjective + -ism.