CAPS LOCK IS A BUTTON ON A COMPUTER KEYBOARD THAT, WHEN PRESSED, CAUSES ALL LETTERS TO BE WRITTEN IN CAPTIALS UNTIL DEACTIVATED. IT IS LOCATED IN THE POSITION OF A SIMILAR SHIFT LOCK KEY (AND SOMETIMES A CTRL KEY) FOUND IN SOME OTHER KEYBOARD LAYOUTS. IT IS USUALLY A TOGGLE KEY: EACH PRESS REVERSES IT'S ACTION.