backslash

The punctuation mark \.

Used erroneously in reference to, or in reading out, the ordinary slash, that is, the punctuation mark /.

[…] I was trying to find a web-site for which I had been given the following address: http://www.isop.ucla.edu/pacrim/pubs/korjournal.htm. […] I began to work backwards, removing first the last part of the address following the last backslash (/korjournal.htm).

“So, do what I tell you. Open a browser window and type this in the menu^([sic]) bar: F-T-P colon backslash backslash euronews dot net backslash...” I pecked carefully at the keyboard as he dictated a URL that was about fifty characters long, […]

To escape (a metacharacter) by prepending a backslash that serves as an escape character, thereby forming an escape sequence.