The Collaborative International Dictionary
ball cap
Flobert \Flo"bert\, n. (Gun.) A small cartridge designed for target shooting; -- sometimes called ball cap.
Flobert rifle, a rifle adapted to the use of floberts.
Usage examples of "ball cap".
He had extracted a promise from her that she'd wear a kerchief or a baseball cap over the dye-job, but promises were made to be broken.