An email address is a unique identifier used to send and receive messages over the internet. It typically consists of two main parts: the local part, which identifies the user, and the domain part, which indicates the email service provider. For example, in the email address user@example.com, "user" is the local part, and "example.com" is the domain. Email addresses are essential for communication in both personal and professional settings. They allow users to exchange messages, share files, and connect with others globally. Common email service providers include Gmail, Yahoo Mail, and Outlook.