stamp duty

A tax or duty imposed on pieces of parchment or paper, on which many kinds of legal instruments are written. Documents which are liable to stamp-duty are not admi ible in evidence unle they bear the stamp required by law. ( Eng.) stamp-hammer, subst . A direct-acting hammer where the hammer-block is lifted vertically, either by cams or friction-rollers, or by steam or water pre ure acting on a piston in a closed cylinder. ( Percy .)