Entry 1 sense Webster, 1913 Nestorianism /nĕs-tôr'-ē-ən-ĭzˌ-əm/ · Nes·to·ri·an·ism · IPA /nɛstˈɔriːənˌɪzəm/ 01 n. The doctrines of the Nestorian Christians, or of Nestorius. 1. The doctrines of the Nestorian Christians, or of Nestorius.