The at sign, @, is an accounting and invoice abbreviation meaning "at a rate of", now seen more widely in email addresses and social media platform handles. It is normally read aloud as "at" and is also commonly called the at symbol, commercial at, or address sign.

Electronic mail is a method of transmitting and receiving messages using electronic devices. It was conceived in the late–20th century as the digital version of, or counterpart to, mail. Email is a ubiquitous and very widely used communication medium; in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries.