IMAP: see Internet Messaging Access Protocol mail server.
Internet Messaging Access Protocol (IMAP) mail server: A common mail server used for Internet email, similar to POP3, but in addition to holding incoming email messages until you log in to the email account and download the messages, it allows you to archive email messages into folders, share mailboxes with other users, access multiple mail servers at one time, and more efficiently access email attachments.
Internet Protocol (IP): The protocol used to format packets and rules of transmission and reception over the Internet.
IP address: The numeric identifier for a computer or device on the Internet. The format of an IP address is a 32-bit numeric address written as four numbers separated by periods. Each number can be zero to 255.
IP-based domain: A domain with a unique IP address.