Definition of caps lock
: a function on a computer keyboard that mimics the effect of holding down a shift key Depending on the way the terminal or keyboard is designed, when caps lock is in effect the shift key may be ignored or it may cause a reverse shift: when the caps lock is in effect, the shift key puts letters back into lowercase. — Infoworld
First Known Use of caps lock
Learn More about caps lock
Seen and Heard
What made you want to look up caps lock? Please tell us where you read or heard it (including the quote, if possible).