The Collaborative International Dictionary of English v.0.48:

Abyssinia \Abyssinia\ n.
   1. same as Ethiopia.

   Syn: Ethiopia, Yaltopya
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Abyssinia
    n 1: Ethiopia is a republic in northeastern Africa on the Red
         Sea; formerly called Abyssinia [syn: Ethiopia, Federal
         Democratic Republic of Ethiopia, Yaltopya, Abyssinia]