a heavy metal ball secured by a chain to the leg of a prisoner to prevent escape (用链系于犯人腿上以防逃跑的沉重金属球)球镣 ■used in similes and metaphors to convey the idea that someone or something is a crippling encumbrance [用于明喻或暗喻]障碍;累赘 the ball and chain of debt. 债务牵累。