Cannonballs were fired into the castle walls.
Sports term; the heavy metal ball used in the shot put event. Often appears in the compound 砲丸投げ (shot put).
See also: 砲丸投げ
He threw the shot a long way.
The shot put athlete practices every day.
shot put
Compound of 砲 (cannon) and 丸 (ball, round object). The sports sense is an extension from the cannonball shape.