also: うちうみ
noun
inland sea; inlet; gulf; bay
Refers to a body of water largely surrounded by land, such as the Seto Inland Sea (瀬戸内海). Can also be used for smaller inlets and bays.
瀬戸内海は日本で一番大きな内海です。
The Seto Inland Sea is the largest inland sea in Japan.
この内海にはたくさんの小さな島がある。
There are many small islands in this inland sea.
noun
Only with reading うちうみ
Archaic meaning, now largely replaced by 湖 (みずうみ). Found in old texts or place names.
古い文献では、内海が湖を指すことがある。
In old documents, 内海 (うちうみ) can refer to a lake.