The Collaborative International Dictionary of English v.0.48:

Casino \Ca*si"no\, n.; pl. E. Casinos, It. Casini. [It.
   casino, dim. of casa house, fr. L. casa cottage. Cf.
   Cassing.]
   1. A small country house.
      [1913 Webster]

   2. A building or room used for meetings, or public
      amusements, for dancing, etc., sometimes having gambling
      tables or devices.
      [1913 Webster +PJC]

   3. A game at cards. See Cassino.
      [1913 Webster]

   4. a business establishment for which the primary business is
      gambling, having various types of gambling tables, such as
      blackjack or roulette, and usually also slot machines, and
      sometimes other forms of gambling, such as poker; also,
      the main room of such an establishment where the gambling
      is conducted; as, the Trump casinos in Atlantic City.
      [PJC]