Definition of Cryptographic Certificate
A Cryptographic Certificate is a user's Public Key, which has been signed and encrypted using the private key of a well-known Certificate Authority. This allows the user to give out his or her Public Key to others, and allows those others to trust that it is, in fact, the user's correct Public Key.
This trust is established by a community agreement to trust the Cryptographic Certificate organization to verify the identity of users, and to sign their Public Key's, thereby certifying that they belong to who they say they belong to.
A popular format for Cryptographic Certificate is X.509.