The Collaborative International Dictionary of English v.0.48:

Raja \Ra"ja\ (r[aum]"j[aum] or r[=a]"j[.a]), n.
   Same as Rajah.
   [1913 Webster]

WordNet (r) 3.0 (2006):

raja
    n 1: a prince or king in India [syn: raja, rajah]
    2: type genus of the family Rajidae [syn: Raja, genus Raja]