柯林斯詞典mortarboard (mortarboards) 1. N-COUNT A mortarboard is a stiff, black cap which has a flat, square top with a bunch of threads attached to it. In the United States, mortarboards are worn by students at graduation ceremonies at high schools, colleges, and universities. 學(xué)位帽 返回 mortarboard劍橋詞典a black hat with a square , flat top , worn for formal occasions and ceremonies by some teachers and students at a college or university , and in the past by some schoolteachers （黑色的）方頂帽，學(xué)位帽 返回 mortarboard