On computer keyboards, the Esc key Esc (named Escape key in the international standard series ISO/IEC 9995) is a key used to generate the escape character (which can be represented as ASCII code 27 in decimal, Unicode U+001B, or Ctrl+[). The escape character, when sent from the keyboard to a computer, often is interpreted by software as "stop", "cancel" or "exit", and when sent from the computer to an external device (including many printers since the 1980s, computer terminals and Linux consoles, for example) marks the beginning of an escape sequence to specify operating modes or characteristics generally.
It is now generally placed at the top left corner of the keyboard, a convention dating at least to the original IBM PC keyboard, though the key itself originated decades earlier with teletypewriters.