Republic of Korea re·pub·li·cofkorea uncommon noun 1. a republic in the southern half of the Korean Peninsula; established in 1948 SynonymsSouth KoreaRepublic of Korea Related words Broader terms Asian country Parts KoreaAsia Part of SeoulInchonKwangjuTaeguPusan WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.