ˌkɑn.fəɹˈmeɪ.ʃən ˌkɒn.fəˈmeɪ.ʃən a sacrament admitting a baptized person to full participation in the church a ceremony held in the synagogue (usually at Pentecost) to admit as adult members of the Jewish community young men and women who have successfully completed a course of study in Judaism additional proof that something that was believed (some fact or hypothesis or theory) is correct fossils provided further confirmation of the evolutionary theory information that confirms or verifies making something valid by formally ratifying or confirming it the ratification of the treaty confirmation of the appointment