The Collaborative International Dictionary of English v.0.48:

Marketable \Mar"ket*a*ble\, a.
   1. Fit to be offered for sale in a market; such as may be
      justly and lawfully sold; as, dacayed provisions are not
      marketable.
      [1913 Webster]

   2. Current in market; as, marketable value.
      [1913 Webster]

   3. Wanted by purchasers; salable; as, furs are not marketable
      in that country.
      [1913 Webster]

WordNet (r) 3.0 (2006):

marketable
    adj 1: being in demand by especially employers; "marketable
           skills"
    2: fit to be offered for sale; "marketable produce" [syn:
       marketable, merchantable, sellable, vendable,
       vendible]
    3: capable of being marketed; "the marketable surplus"