Definition of "Confirmation" :

noun: a sacrament admitting a baptized person to full participation in the church

noun: 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

noun: additional proof that something that was believed (some fact or hypothesis or theory) is correct

"Fossils provided further confirmation of the evolutionary theory."

noun: information that confirms or verifies

noun: making something valid by formally ratifying or confirming it

"Confirmation of the appointment."