The Collaborative International Dictionary of English v.0.48:

Seron \Se*ron"\, Seroon \Se*roon"\, n. [Sp. seron a kind of
   hamper or pannier, aug. of sera a large pannier or basket.]
   Same as Ceroon.
   [1913 Webster]

   Note: This word as expressing a quantity or weight has no
         definite signification. --McElrath.
         [1913 Webster]