triangular bipyramid双三角锥
bipyramid blender双锥混合器
regular bipyramid正双棱锥
tetragonal bipyramid正方双锥
trigonal bipyramid三角双锥;三方双锥;三角双锥体
hexagonal bipyramid六方双锥
pentagonal bipyramid五角双锥;双五角锥
dihexagonal bipyramid复六方双锥
bipyramid d双锥
N（名词） a geometrical form consisting of two pyramids with a common polygonal base 双棱锥