The Collaborative International Dictionary of English v.0.48:

Stanhope \Stan"hope\ (st[a^]n"h[=o]p; colloq. st[a^]n"[u^]p), n.
   A light two-wheeled, or sometimes four-wheeled, carriage,
   without a top; -- so called from Lord Stanhope, for whom it
   was contrived.
   [1913 Webster]

WordNet (r) 3.0 (2006):

stanhope
    n 1: a light open horse-drawn carriage with two or four wheels
         and one seat