A more thorough explanation:

A port of entry is a place where people and goods are allowed to enter a country and where customs officials are stationed. It can also refer to a harbor where ships load and unload cargo.

• Foreign port: A port that is exclusively within the jurisdiction of another country or state.
• Free port: A port located outside a country's customs frontier, where goods may be delivered without being subjected to customs-control procedures or import duties.
• Home port: The port where a vessel is registered or where its owner resides.
• Port of call: A port where a ship stops during a voyage.
• Port of delivery: The port that is the terminus of any particular voyage and where the ship unloads its cargo.
• Port of departure: The port from which a vessel departs on the start of a voyage.
• Port of destination: The port at which a voyage is to end, including any stopping places where the ship receives or unloads cargo.
• Port of discharge: The place where a substantial part of the cargo is discharged.

For example, if a ship is traveling from China to the United States, the first port it arrives at in the US is considered a port of entry. Customs officials will be stationed there to inspect the ship and its cargo to ensure that everything is legal and safe to enter the country. Similarly, a free port may be used for storing goods that will be shipped to other countries without being subject to import duties or taxes. A home port is where a ship is registered or where its owner resides, and a port of call is a stop along a ship's journey where it may take on or unload cargo or passengers.