The Collaborative International Dictionary of English v.0.48:

Grapeshot \Grape"shot`\, n. (Mil.)
   A cluster, usually nine in number, of small iron balls, put
   together by means of cast-iron circular plates at top and
   bottom, with two rings, and a central connecting rod, in
   order to be used as a charge for a cannon. Formerly grapeshot
   were inclosed in canvas bags.
   [1913 Webster]

WordNet (r) 3.0 (2006):

grapeshot
    n 1: a cluster of small projectiles fired together from a cannon
         to produce a hail of shot [syn: grapeshot, grape]

The Devil's Dictionary (1881-1906):

GRAPESHOT, n.  An argument which the future is preparing in answer to
the demands of American Socialism.