Pusan, city in southeastern South Korea, on Korea Strait. Pusan is the second largest South Korean city and the principal seaport in the republic. Industrial establishments in the city include shipyards, railroad workshops, rubber factories, ironworks, textile mills, rice and salt refineries, and fisheries. The port has ferry service to the Japanese port of Shimonoseki. Pusan has several universities, among them Pusan National University (1946).