di.he.dral
adj.Mathematics （形容词）【数学】 Formed by or having two plane faces; two-sided.由两个平面构成的；二面的Relating to, having, or forming a dihedral angle.二面角的：关于、具有、或构成二面角的n.（名词）Mathematics A dihedral angle.【数学】 二面角Aeronautics The upward or downward inclination of an aircraft wing from true horizontal.【航空学】 上反角，下反角：飞行器的机翼与水平面向上或向下的倾斜角
