1. a unit of apothecary weight equal to 24 grains;
The Collaborative International Dictionary of English v.0.48:
Pennyweight \Pen"ny*weight`\, n.
A troy weight containing twenty-four grains, or the twentieth
part of a troy ounce; 1.555 grams; as, a pennyweight of gold
or of arsenic. It is abbreviated dwt or pwt. It was anciently
the weight of a silver penny, whence the name.
[1913 Webster + PJC]
WordNet (r) 3.0 (2006):
n 1: a unit of apothecary weight equal to 24 grains
Bouvier's Law Dictionary, Revised 6th Ed (1856):
PENNYWEIGHT. A troy weight which weighs twenty-four grains, or one-twentieth
part of an ounce. Vide Weights.