（传说中海里的大龟或大鳖） a huge legendary turtle ◆鳌背负山 One's indebtedness to sb. is as great as the load of a mountain to a turtle;feel very much indebted to sb.； 鳌头独占 take possession of the sea monster's head;be the champion;come out first [top;at the top];head the list of successful candidates;perch alone on the whale's head