D defs.my
Entry 1 sense Webster, 1913

Macropinacoid

· Mac·ro·pin·a·coid · IPA
01 n. One of the two planes of an orthorhombic crystal which are parallel to the vertical and longer lateral (macrodiagonal) axes.
  1. 1.
    One of the two planes of an orthorhombic crystal which are parallel to the vertical and longer lateral (macrodiagonal) axes.(Crystallog.)