The smallest of the four main islands of Japan, constituting an administrative region; population 4,142,000 (est. 2005); capital, Matsuyama. It is divided from Kyushu to the west and southern Honshu to the north by the Inland Sea.
Definition of Shikoku in US English:
Shikoku
proper nounSHəˈkōˌko͞o
The smallest of the four main islands of Japan, an administrative region; population 4,142,000 (est. 2005); capital, Matsuyama. The Inland Sea separates it from Kyushu on the west and Honshu on the north.