The Collaborative International Dictionary of English v.0.48:

Korea \Korea\ prop. n.
   An Asian peninsula off Manchuria.

   Syn: Korean Peninsula.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Korea
    n 1: an Asian peninsula (off Manchuria) separating the Yellow
         Sea and the Sea of Japan; the Korean name is Dae-Han-Min-
         Gook or Han-Gook [syn: Korea, Korean Peninsula, Dae-
         Han-Min-Gook, Han-Gook]