ball (small, used in games or sports — e.g., tennis, baseball, ping-pong)
Il m'a lancé la balle pendant le match.
He threw the ball to me during the match.
bullet (ammunition fired from a firearm)
Il a été touché par une balle.
He was hit by a bullet.
informal: euro (money)
Ça coûte cent balles.
That costs a hundred euros.