trinitarianism
notion applied to those who believe in an ontological as well as those who believe in a theological trinity; that is to say, who recognise the like principle pervading the universe of being
en-US/ˌtɹɪnɪˈtɛɹiəˌnɪzəm/
en-GB/tɹɪnɪtɛəɹɪənɪzəm/