n.
Pronunciation: ə - ' no ̇ r-th ə - ˌ s ī t
Function: noun
Etymology: French anorthose, a feldspar, from a- + Greek orthos ― more at ORTH-
Date: 1863
: a granular plutonic igneous rock composed almost exclusively of a soda-lime feldspar (as labradorite)
– an · or · tho · si · tic \ ə - ˌ no ̇ r-th ə - ' si-tik \ adjective