Bipyramidal
Pronunciation : Bi`py*ram"i*dal
Part of Speech : a.
Etymology : [Pref. bi- + pyramidal.]
Definition : Defn: Consisting of two pyramids placed base to base; having a pyramid at each of the extremities of a prism, as in quartz crystals.
Source : Webster's Unabridged Dictionary, 1913
Merriam-Webster's Everyday Language Reference Set: Includes: The Merriam-Webster Dictionary, The Merriam-Webster Thesaurus, and The Merriam-Webster Vocabulary Builder