Webster's Revised Unabridged Dictionary · 1913

Heeltap

Heeltap , noun

1.
One of the segments of leather in the heel of a shoe.
2.
A small portion of liquor left in a glass after drinking.
Bumpers around and no heeltaps. — Sheridan

Heeltap , transitive verb

To add a piece of leather to the heel of (a shoe, boot, etc.)