A more thorough explanation:

A port is a place where ships can load and unload cargo. It can also refer to a place where people and goods are allowed to enter a country and where customs officials are stationed. Some examples of different types of ports include:

• Port of entry: A place where people and goods can enter a country. Customs officials are stationed here to check for any illegal items or substances.
• 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 can 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 where a ship unloads its cargo at the end of a particular voyage.
• Port of departure: The port from which a vessel departs at the start of a voyage.
• Port of destination: The port where a voyage is intended to end, including any stopping places where cargo is loaded or unloaded.
• Port of discharge: The place where a substantial part of the cargo is unloaded.

For example, a cargo ship may stop at a port of call to unload some of its cargo before continuing on to its port of delivery. A traveler entering a country may go through customs at a port of entry before being allowed to enter the country. A company may choose to store goods in a free port to avoid paying import duties or taxes.