ˈtraˌkīt, ˈtrāˌ- noun
( -s )
Etymology: French, from Greek trachys rough + French -ite — more at trachea
: a usually light-colored volcanic rock consisting of potash feldspar generally with more or less biotite, amphibole, or pyroxene, commonly exhibiting a subparallel texture, and being the effusive form of syenite