one of a pair of opposite parallel faces of a crystal
2.
a crystal that contains a pair of opposite parallel faces
pinacoid in American English
(ˈpɪnəˌkɔid)
noun
Crystallography
a form whose faces are parallel to two of the axes
Derived forms
pinacoidal
adjective
Word origin
[1875–80; ‹ Gk pinak- (s. of pínax) slab, board + -oid]This word is first recorded in the period 1875–80. Other words that entered Englishat around the same time include: Diaspora, massage, neoclassic, slime mold, weekend-oid is a suffix meaning “resembling,” “like,” used in the formation of adjectives andnouns (and often implying an incomplete or imperfect resemblance to what is indicatedby the preceding element). Other words that use the affix -oid include: anthropoid, cardioid, cuboid, lithoid, ovoid