pinacoid

[ pin-uh-koid ]
/ ˈpɪn əˌkɔɪd /

noun Crystallography.

a form whose faces are parallel to two of the axes.

Origin of pinacoid

1875–80; < Greek pinak- (stem of pínax) slab, board + -oid

OTHER WORDS FROM pinacoid

pin·a·coi·dal, adjective