seaport

...a port located on a river and used mainly for inland waterway traffic. Even if it is located on an inland river, if it is connected to overseas ports by sea routes, such as London, Wuhan, or Montreal, it is called a seaport and not a river port. In Japan before the Meiji period, rivers were important transportation routes, and rice, firewood, and charcoal were transported down from the interior in small flat-bottomed river boats, and salt and salted and dried fish were transported up from the coast.

*Some of the terminology that mentions "seaport" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…河川沿岸に位置し，もっぱら内陸水路の交通にかかわる港。たとえ内陸の川のほとりにあっても，ロンドン，武漢，モントリオールなどのように海外の港と海上航路で結ばれているものは港湾seaportであって，河港とは呼ばれない。明治期以前の日本では河川が重要な輸送路になり，奥地からは米や薪炭などが平底の小さい川船で下航し，海岸からは塩や塩乾魚などが上航していた。…

※「seaport」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報