The Collaborative International Dictionary of English v.0.48:

Galena \Ga*le"na\, n.[L. galena lead ore, dross that remains
   after melting lead: cf. F. gal[`e]ne sulphide of lead ore,
   antidote to poison, stillness of the sea, calm, tranquility.]
   [1913 Webster]
   1. (Med.) A remedy or antidote for poison; theriaca. [Obs.]
      --Parr.
      [1913 Webster]

   2. (Min.) Lead sulphide; the principal ore of lead. It is of
      a bluish gray color and metallic luster, and is cubic in
      crystallization and cleavage.
      [1913 Webster]

   False galena. See Blende. Galenic

WordNet (r) 3.0 (2006):

galena
    n 1: soft blue-grey mineral; lead sulfide; a major source of
         lead