The Collaborative International Dictionary of English v.0.48:

Lusitania \Lusitania\ n.
   An ancient region and Roman province of the Iberian
   peninsula, corresponding roughly to modern Portugal and parts
   of Spain.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

Lusitania
    n 1: ancient region and Roman province on the Iberian Peninsula;
         corresponds roughly to modern Portugal and parts of Spain