ecclesiasticEnglishOxford New American Dictionaryecclesiastic /əˌklēzēˈastik, əˌkliziˈæstɪk / formal ▸ noun a priest or member of the clergy. ▸ adjective another term for ecclesiastical. – ORIGIN late Middle English : from French ecclésiastique, or via late Latin from Greek ekklēsiastikos, from ekklēsiastēs ‘member of an assembly’, from ekklēsia ‘assembly, church’, based on ekkalein ‘summon out’.