Anorthite

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Anorthite \A*nor"thite\, n. [Gr. 'an priv. + 'orqo`s straight
     ('orqh` sc. gwni`a right angle); not in a right angle.]
     A mineral of the feldspar family, commonly occurring in small
     glassy crystals, also a constituent of some igneous rocks. It
     is a lime feldspar. See {Feldspar}.
     [1913 Webster]



From WordNet (r) 2.0 [wn]:

  anorthite
       n : rare plagioclastic feldspar occurring in many igneous rocks