Anorthite

1. n. 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.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.