Shorthand and popular terrm for electronic mail, or the sending of messages over the Internet (or other network), in contrast to so-called Snail Mail (term used by Internet avatars to refer to conventional post-office-based mail). E-mail is a basic feature of any network or Internet service provider. In this latter manner, a message is composed in an editor and sent to a mail server (or a pop) where it is sent to the indicated address. An E-mail address comprises at least three basic elements: a name, usually a single word in all caps or all lowercase letters (i.e., joesmith); a domain, preceded by the "at" sign (@) and indicating the server which distributes mail to the individual (i.e., aol for America Online); and a three-letter extension indicating the nature of the domain such as .com for a general communications domain, .net for a local network, .edu for an educational domain like a university, .org for an organization such as PBS, or .gov for a government organization. E-mail is increasingly being supplied as a basic part of a computer's operating system. Most e-mail systems allow for attaching files.