The Collaborative International Dictionary of English v.0.48:

Heeltap \Heel"tap`\, n.
   1. One of the segments of leather in the heel of a shoe.
      [1913 Webster]

   2. A small portion of liquor left in a glass after drinking.
      "Bumpers around and no heeltaps." --Sheridan.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Heeltap \Heel"tap`\, v. t. [imp. & p. p. Heeltapped; p. pr. &
   vb. n. Heeltapping.]
   To add a piece of leather to the heel of (a shoe, boot, etc.)
   [1913 Webster]