Backslash ... The backslash \ is a typographical mark used mainly in computing and mathematics. It is the mirror image of the common slash ('solidus'), /. It is a relatively recent mark, first documented in the 1930s. The backward slash symbol "\" is primarily used in computing and programming as an escape character. Learn how to easily type the backslash symbol on your keyboard with our step-by-step guide for all users. Also called a backward slash, downward slash, and reverse solidus, the backslash is a character ( \ ) introduced by Bob Bemer in 1960. Although "slash" often describes the forward slash, it can describe either a forward slash or backslash. It's better to say "backslash" or "whack" instead of "slash" when telling someone to enter a backslash. The meaning of BACKSLASH is a mark \ used especially in computer programming. What is a backslash? A backslash is a symbol that resembles a line slanted toward the left ( \ ). It is a “backwards slash” that is the reverse of a forward slash ( / ). The backslash has no usage in formal or informal writing. It is called a "backslash" because it is the reverse of the slash (/) or forward slash. The backslash is used in several computer systems, and in many programming languages such as C and Perl. The backslash key is located above the Enter key and below the Backspace key on the keyboard. It is typically positioned to the left of the Enter key and looks like this \. The slash is a slanting line punctuation mark /. It is also known as a stroke or solidus, a forward slash and several other historical or technical names. The most well-known instance of this is regular expression syntax, in which a backslash escape other characters in order to either give them special meaning or take away a special meaning they might have.