trencher
noun [ C ] uk/ˈtren.tʃər/ us/ˈtren.tʃɚ/
Australian English（黑色的）方顶帽，学位帽
a black hat with a square, flat top, worn on formal occasions by some teachers and students at college or university, and in the past by some school teachers
Compare: mortarboard
（旧时盛食物用的）木盘
in the past, a flat, wooden dish used to serve food