The Collaborative International Dictionary
Brachypinacoid
Brachypinacoid \Brach`y*pin"a*coid\, n. [Gr. brachy`s short + E. pinacoid.] (Crytallog.) A plane of an orthorhombic crystal which is parallel both to the vertical axis and to the shorter lateral (brachydiagonal) axis. [1913 Webster] ||
Wiktionary
brachypinacoid
n. (context crystallography English) A plane of an orthorhombic crystal which is parallel both to the vertical axis and to the shorter lateral (brachydiagonal) axis.