A host server which holds email messages for clients. The client (the program you use to get your email) connects to the mail server and retrieves any messages that are waiting for you.
A computer responsible for processing and/or storing e-mail. It is the electronic equivalent of a post office. E-mail accounts exist on a mail server, where e-mail messages are stored until retrieval by the e-mail client.
Program that stores and forwards Internet mail, according to Internet protocols such as IMAP, SMTP, or POP. Examples of mail servers on Macintosh are AppleShare IP Mail Server and Eudora Internet Mail Server (EIMS). Also the computer that a mail server program runs on.