Source : Webster's Revised Unabridged Dictionary (1913)

Syenite \Sy"e*nite\, n. [L. Syenites (sc. lapis), from Syene,
   Gr. ?.] (Min.)
   (a) Orig., a rock composed of quartz, hornblende, and
       feldspar, anciently quarried at Syene, in Upper Egypt,
       and now called {granite}.
   (b) A granular, crystalline, ingeous rock composed of
       orthoclase and hornblende, the latter often replaced or
       accompanied by pyroxene or mica. Syenite sometimes
       contains nephelite (el[ae]olite) or leucite, and is then
       called {nephelite (el[ae]olite) syenite} or {leucite
       syenite}.