A more thorough explanation:

Flag state refers to the country under whose flag a ship is registered. A ship can only fly the flag of one state at a time.

For example, if a ship is registered in Panama, it is considered a Panamanian-flagged vessel and is subject to the laws and regulations of Panama. The flag state is responsible for ensuring that the ship complies with international maritime laws and regulations, including safety, security, and environmental standards.

Another example is a ship registered in Liberia. It is considered a Liberian-flagged vessel and is subject to the laws and regulations of Liberia. The flag state is responsible for conducting inspections and issuing certificates to ensure that the ship is seaworthy and meets all safety requirements.

In summary, the flag state is the country that a ship is registered under and is responsible for ensuring that the ship complies with international maritime laws and regulations.