The Collaborative International Dictionary of English v.0.48:

Budapest \Budapest\ prop. n. (Geography)
   The capital city of Hungary. Population (2000) = 2,008,546.
   [PJC]

WordNet (r) 3.0 (2006):

Budapest
    n 1: capital and largest city of Hungary; located on the Danube
         River in north-central Hungary [syn: Budapest, Hungarian
         capital, capital of Hungary]