something which validates or confirms the authenticity of something
proof of the identity of a user logging on to some network
a hallmark or assay-mark on a piece of metalwork
A verification that something is true or has happened.
An official indicator that things will happen as planned.
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.
An act whereby something conditional or voidable is made sure and unavoidable, especially the possession of an estate.