What is the full form of IMAP?

Full-form / acronym-expansion questions on networking protocols test both the exact standard wording and the protocol's underlying role. IMAP (RFC 3501) is one of the two dominant protocols — alongside POP3 — that a mail client uses to retrieve email from a server, and its core idea is letting the client repeatedly access messages that stay stored on the server, rather than downloading and removing them.

Expanding the acronym letter by letter:

1. I — Internet: it operates over any standard Internet/TCP-IP connection.

2. M — Message: it manages individual, stored email messages on the server.

3. A — Access: its defining behaviour is giving the client ongoing access to those messages, not a one-time transfer.

4. P — Protocol: a formally defined set of client-server communication rules.

Put together, this gives Internet Message Access Protocol. As a cross-check, contrast IMAP with POP3 (Post Office Protocol), which downloads mail and typically removes it from the server — IMAP's whole purpose is enabling multi-device access, which is exactly why an 'access' idea (not a one-time transfer) belongs in its name. This also rules out framings of IMAP as an international governance standard, a live chat/messaging service, an authority-granting mechanism, or a permission system — none of which match what IMAP actually does.