On the Internet, a computer program used to send out mass e-mailings. Typically, one sends an e-mail message to a group of people by entering one address in the "to" line, and cc-ing everyone else. With very large mailing lists (such as newsletters, for example), this is impractical, so the message is sent to a single e-mail address, which then automatically distributes the message to all those on the mailing list. Listserver is abbreviated listserv. Some common listservers that are encountered are "majordomo," "mailserv," and "almanac."