The Collaborative International Dictionary of English v.0.48:

Pilon \Pi*lon"\, n. [Sp., sugar loaf.] [Sp. Amer.]
   1. A conical loaf of sugar.
      [Webster 1913 Suppl.]

   2. A gratuity given by tradesmen to customers settling their
      accounts. [Southern U. S.]
      [Webster 1913 Suppl.]