The Internet Message Access Protocol (IMAP) is a standard protocol used by email clients to retrieve messages from a mail server. Unlike other protocols, such as Post Office Protocol (POP), IMAP allows users to access their emails from multiple devices while keeping the messages stored on the server. This means that any changes made, like reading or deleting emails, are synchronized across all devices. IMAP operates over the internet, enabling users to manage their email folders and organize messages efficiently. It supports features like searching for specific emails and flagging important messages, making it a popular choice for both personal and professional email management.