Source : Webster's Revised Unabridged Dictionary (1913)

Manganese \Man`ga*nese"\, n. [F. mangan[`e]se, It. manganese,
   sasso magnesio; prob. corrupted from L. magnes, because of
   its resemblance to the magnet. See {Magnet}, and cf.
   {Magnesia}.] (Chem.)
   An element obtained by reduction of its oxide, as a hard,
   grayish white metal, fusible with difficulty, but easily
   oxidized. Its ores occur abundantly in nature as the minerals
   pyrolusite, manganite, etc. Symbol Mn. Atomic weight 54.8.

   Note: An alloy of manganese with iron (called ferromanganese)
         is used to increase the density and hardness of steel.

   {Black oxide of manganese}, {Manganese dioxide or peroxide},
      or {Black manganese} (Chem.), a heavy black powder {MnO2},
      occurring native as the mineral pyrolusite, and valuable
      as a strong oxidizer; -- called also familiarly
      {manganese}. It colors glass violet, and is used as a
      decolorizer to remove the green tint of impure glass.

   {Manganese bronze}, an alloy made by adding from one to two
      per cent of manganese to the copper and zinc used in
      brass.