基本解释[動力][車輛] 下止點英英字典柯林斯英英字典 the position of the crank of a reciprocating engine when the piston is at its nearest point to the crankshaft (Also called outer dead centre) bottom dead centre剑桥字典bottom dead centre柯林斯字典专业释义交通運輸工程下止點下死點物理學下止點下死點