Ancient Greek πινάκιον(pinákion, slab, tablet) + -oid.


pinacoid ‎(plural pinacoids)

  1. (crystallography) The face of a crystal parallel to two of the axes.
    • 2009 January 16, Juan Manuel Garcia-Ruiz et al., “Morphogenesis of Self-Assembled Nanocrystalline Materials of Barium Carbonate and Silica”, in Science[1], volume 323, number 5912:
      The crystallographic symmetry is initially broken toward dilation symmetry by the splitting of the basal pinacoid or the pseudohexagonal bipyramidal faces of the growing crystal core.