The Collaborative International Dictionary of English v.0.48:

Mascot \Mas"cot\, Mascotte \Mas"cotte\, n. [Through French fr.
   Pr. mascot a little sorcerer or magician, mascotto
   witchcraft, sorcery.]
   1. A person who is supposed to bring good luck to the
      household to which he or she belongs.
      [1913 Webster]

   2. Hence: Anything that brings good luck; especially, an
      animal kept by a group, as a sports team, to serve as a
      symbol and to bring luck.
      [1913 Webster +PJC]