num.第五；n.五分之一；第五音，五度音程；五分之一加仑（瓶）； 变形： 复数：fifths 英英释义： fifth[ fifθ ]n.a quantity of liquor equal to one fifth of a United States gallonposition five in a countable series of things"he was fifth out of several hundred runners"one part in five equal parts同义词