polar trihedral[数] 极三面形
coordinate trihedral[数] 坐标三面形
trihedral rule三棱尺
trirectangular trihedral[数] 三直角三面形
trihedral vertex[数] 三面顶点
principal trihedral主要三面形
trihedral reflector三面反射镜
moving trihedral怜三面形;[数] 活动三面形;动三面形;[数] 动标三面形
trihedral prism三面体棱镜;三角棱镜
ADJ（形容词） having or formed by three plane faces meeting at a point 有三面的
N（名词） a figure formed by the intersection of three lines in different planes 三面体