Authentication is the process of verifying the identity of a user, device, or system. It is a security mechanism used to ensure that the person or entity attempting to access a resource is authorized to do so.
An example of authentication is when you log in to your email account using your username and password. The system checks your credentials against a database of authorized users to verify that you are who you claim to be. If your credentials match, you are granted access to your email account. This helps to prevent unauthorized access to your emails and protect your personal information.