basalt
ba.salt \b*-'so.lt, 'ba--.\ \b*-'so.l-tik\ n [L basaltes, MS var. of basanites touchstone, fr. Gk basanite]-s (lithos), fr. basanos touchstone, fr. Egypt bhsub-breve>nw : a dark gray to black dense to fine-grained igneous rock that consists of basic plagioclase, augite, and usu. magnetite - ba.sal.tic aj