Confirmation

Noun

1. An official indicator that things will happen as planned.

   "We will send you a written confirmation of your hotel booking."

2. A verification that something is true or has happened.

   "The announcement in the newspaper was a confirmation of my suspicions."

3. A ceremony of sealing and conscious acknowledgement of the faith in many Christian churches, typically around the ages of 14 to 18; considered a sacrament in some churches, including Catholicism, but not in most Protestant churches.
4. An act whereby something conditional or voidable is made sure and unavoidable, especially the possession of an estate.