On most keyboards, the backslash key is located either below or above the enter key or placed directly to the left of the enter key. On English keyboards, it is found on the same key as the pipe key. On Apple keyboards, it is directly above the enter key.

The backslash key, also called a reverse solidus or a backward slash, was first introduced in 1960 by Bob Bemer. It has two basic functions. It can be used as an escape character or as a separator in a file path for Windows files and directories.

A major distinction between the backslash key and forward slash key is that a backslash has a pipe character above it, while a forward slash has a question mark above it.