The Print Screen key is more useful under DOS than under Windows. Under DOS pressing the Print Screen key immediately sends the contents of the screen to the printer. Under Windows pressing the Print Screen key sends a copy of the screen to the Clipboard. You must then paste to an appropriate program and print from there.

This button is intended to print whatever is on your screen. If you are using DOS, or you are in your BIOS and have a printer set up, the Print Screen...

An instruction to the computer to print the screen exactly the way it is.

This up on a keyboard is intended to print whatever is on your screen.

Print screen (often abbreviated, such as Prt Scr or Print Scrn) is a key present on most computer keyboards, typically situated in the same section as the break and Scroll lock keys. Print screen is shared with Sys Rq. Under earlier command-line based operating systems, this caused an exact copy of the current screen output to be sent to the standard printer port, usually LPT1.