Ball and chain a heavy metal ball secured by a chain to the leg of a prisoner to prevent escape; used figuratively to convey the idea that someone or something is a crippling encumbrance.
ball-flower an architectural ornament resembling a ball within the petals of a flower.
the ball is in someone's court it is that particular person's turn to act next. The metaphor comes from tennis or a similar ball game where different players use particular areas of a marked court.
ball of fire a person who is full of energy and enthusiasm. Recorded in this sense from the mid 20th century, although earlier in literal use. In the 19th century, ball of fire was also a slang term for a glass of brandy.
a whole new ball game a completely new set of circumstances. Originally North American, referring to a game of baseball.