Orthoclase
Pronunciation : Or"tho*clase
Part of Speech : n.
Etymology : [Ortho- + Gr. (Min.)
Definition : Defn: Common or potash feldspar crystallizing in the monoclinic system and having two cleavages at right angles to each other. See Feldspar.
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