(1) A string of bit combinations that is used to escape from normal data, such as text code points, into control information.
(2) A character that is preceded by a (backslash) and is interpreted to have a special meaning to the operating system.
(3) A sequence of characters that contains the symbol followed by one of the characters: a ,b ,f ,n ,r ,t ,v ,' , ,x , , or by one or more octal or hexadecimal digits.