An archaic symbol used in pricing (i.e., 2 doughnuts @ $1 ea.) now rendered ubiquitous in this age of E-mail. Essentially, the "at" symbol separates the user name from the domain of the mail server in an E-mail address. For example, "firstname.lastname@example.org". Also referred to as the at sign. Also referred to, descriptively, as a cinnamon bun.