from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A variety of diorite consisting chiefly of feldspar.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar.

from the GNU version of the Collaborative International Dictionary of English

  • n. A granular igneous rock composed almost exclusively of a soda-lime feldspar, usually labradorite.

from The Century Dictionary and Cyclopedia

  • n. In petrography, a granular or gneissoid igneous rock of eastern Canada, consisting chiefly of the plagioclase feldspar, labradorite.


French anorthose, a kind of feldspar (Greek an-, not; see a-1 + Greek orthos, straight) + -ite1.
(American Heritage® Dictionary of the English Language, Fourth Edition)



Log in or sign up to get involved in the conversation. It's quick and easy.