noun (n)

• a hard brittle grey polyvalent metallic element that resembles iron but is not magnetic; used in making steel; occurs in many minerals(noun.substance)

  Synonym:
  atomic number 25, mn
  

  source: wordnet30
• 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.(noun)

  source: webster1913