a sea in SW Japan, enclosed by the islands of Honshu, Shikoku, and Kyushu. 240 miles (385 km) long.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for inland sea
a sea in SW Japan, between the islands of Honshu, Shikoku, and KyushuJapanese name: Seto Naikai
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012