a key on some computer keyboards that when pressed affects the output of other keys, allowing you to type in capital letters or to type certain numbers and symbols without having to hold down the shift key
shift lock in American English
noun
a typewriter or computer key that locks the shift key in depressed position
Word origin
[1905–10]This word is first recorded in the period 1905–10. Other words that entered Englishat around the same time include: Expressionism, aspect ratio, push-up, thiamine, white list