Honshu n 1: the central and largest of the four main islands of Japan; between the Sea of Japan and the Pacific Ocean; regarded as the Japanese mainland [syn: {Honshu}, {Hondo}]
Honshu \Hon"shu\ prop. n. [Jap.] the main island of Japan. Together with the islands of Hokkaido, Kyushu and Shikoku it forms the bulk of the land area of Japan. [WordNet 1.5]