The Collaborative International Dictionary of English v.0.48:

Raghuvansa \Ragh`u*van"sa\ (r[u^]g`[.u]*v[u^]n"s[.a]), n. [Skr.
   Raguva[.m][,c]a.]
   A celebrated Sanskrit poem having for its subject the Raghu
   dynasty.
   [1913 Webster]