NOUN (2)

1. light carriage; pulled by a single horse;

2. a sedan that has no roof over the driver's seat;

The Collaborative International Dictionary of English v.0.48:

Brougham \Brough"am\, n.
   A light, enclosed carriage, with seats inside for two or
   four, and the fore wheels so arranged as to turn short.
   [1913 Webster]

WordNet (r) 3.0 (2006):

brougham
    n 1: light carriage; pulled by a single horse
    2: a sedan that has no roof over the driver's seat