Definition of west sea:
(n) :
(informal, colloquial) Synonym of Sea of Japan (as found in English, from sources in Japan).
(n) :
(informal, colloquial) Synonym of Qinghai Lake (as found in English, from sources in China).
(n) :
(informal, colloquial) Ellipsis of West Philippine Sea (“South China Sea”), as found in English-language material from the Philippines. [(Philippines, strictly) eastern portion of the South China Sea claimed by the Philippine government to be part of its exclusive economic zone.]
(n) :
(informal, colloquial) Ellipsis of West Korea Sea (“Yellow Sea”), as found in English-language material from Korea.