confirmation
noun
1.
additional proof that something that was believed (some fact or hypothesis or theory) is correct
Derived from:
confirm 2.
3.
4.
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
5.
a sacrament admitting a baptized person to full participation in the church