Wiktionary
fire button
n. (context video games English) A button on a joystick or joypad that corresponds to the action of fire but often represents other in-game actions.
Usage examples of "fire button".
The craft noses were pointed at the opening, and the pilots had their fingers on the FIRE button.
Almost with contempt, Glencannon centered him in his sights and pressed his fire button.
Now the light went out-the cat officer had pushed the fire button.
Hunter flicked his control stick once and depressed his fire button in one fluid motion, rocking the airplane over on its wing and pouring a stream of cannon fire into one of the leading MiGs.
She flipped a couple of interlock switches and pressed the fire button.