It is the mirror image of the common slash /. It is a relatively recent mark, first documented in the 1930s. It is sometimes called a hack, whack, escape (from C/UNIX), reverse slash, slosh, downwhack, backslant, backwhack, bash, reverse slant, reverse solidus, and reversed virgule.

It is also known as a stroke, a solidus, a forward slash and several other historical or technical names. Once used to mark periods and commas, the slash is now used to represent division and fractions, exclusive 'or' and inclusive 'or', and as a date separator. / Slash or solidus.

What is a backslash used for? A backslash is a key on the keyboard used for creating shortcuts and special characters. It can be used to escape quotation marks or other characters, combine words in an URL, and create a line break in Unicode text.

The backslash key is a special computer keyboard key found on most standard keyboards. It's typically located above the Enter/Return key and below the '|' (or backslash) key. The backslash key can enable you to perform various functions depending on what program you're using or where it appears onscreen.