The Collaborative International Dictionary of English v.0.48:

Carboy \Car"boy\ (k[aum]r"boi), n. [Cf. Ir. & Gael carb basket;
   or Pers qur[=a]bah a sort of bottle.]
   A large, globular glass bottle, esp. one of green glass,
   inclosed in basket work or in a box, for protection; -- used
   commonly for carrying corrosive liquids; as sulphuric acid,
   etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

carboy
    n 1: a large bottle for holding corrosive liquids; usually
         cushioned in a special container