かいろ海路kairoうみじ海路umijiうなじ海路unaji
1.
A navigable path on the ocean where ships travel, often used for transport and trade.
2.
The concept of traveling across water by ship, encompassing both the physical routes taken and the journey itself by sea.
3.
A defined maritime passage utilized specifically by vessels, distinguishing it from overland or aerial routes.
Example:
陸路を運ぶのは大変ですが、海路で運ぶのは簡単です。