Inland sea and Lagoon

Inland sea noun - An arm of the Pacific Ocean in southern Japan; surrounded by the islands of Honshu and Shikoku and Kyushu and linked to the Sea of Japan by a narrow channel; the chief port is Hiroshima.

Lagoon and inland sea are semantically related in inland body of water topic. In some cases you can use "Lagoon" instead a noun phrase "Inland sea".

Lagoon noun - A body of water cut off from a larger body by a reef of sand or coral.

Inland sea and lagoon are semantically related in inlet topic. You can use "Inland sea" instead a noun "Lagoon".