Definitions for "User identification"
a series of alphanumeric characters that uniquely identifies
User identification is the process by which a user identifies himself to the system as a valid user. This is not the same as authentication, which is the process of establishing that the user is who he says he is and has a right to use that system.
User identification is the process by which a user identifies himself to the system as a valid user. (As opposed to authentication, which is the process of establishing that the user is indeed that user and has a right to use the system.)