Any of certain keys of a computer keyboard that switch between certain states and are represented by LEDs.

plural of lock key

A keycard.

plural of card key

(computing) Any of a set of keyboard keys marked with directional arrows, used for navigation through documents and lists etc.

plural of arrow key

plural of CD key

A serial key of a program to be installed from a compact disc.

plural of serial key

(computing) A string of characters or equivalent access code that must be input into a program in order to activate it.