There are four main parts of an email address, including the user name, the "@" symbol, the mail server and the top-level domain, according to St. Edward's University. Each email address identifies a unique individual on a mail server so messages can be delivered properly. Various networks have different formats for user names, but every email must have a user name and domain to be useful.
The user name is a nickname, some affectation or a part of a person's real name. For instance, a user name can be a position at a company such as "CEO" or a user name can be part of a name such as "jsmith." Someone's hobby or personal preference can be a user name such as "purplefan" or "baseballjunkie."
The @, or "at" symbol, separates the user name from the second part of the email address, which begins with the mail server.
The mail server usually identifies the institution or company that owns the email server. For instance, "company" owns the mail server at "company.com."
The last part of the email is the top-level domain, which breaks down various websites into hierarchies. Several top-level domains include ".com" used for commercial businesses, ".org" used for non-profit agencies and groups, ".edu" for educational institutions and ".gov" for government agencies.