noun. A service providing the ability to read and send e-mail at a website.

noun. A service for sending, receiving, and/or storing email, usually on a remote web server, in such a way that it is accessible through a web browser.

noun. The email thus stored.

"Drafting a long important e-mail in webmail and then hitting “send” only to find your session has timed out and the e-mail is * gone*."

email