A more thorough explanation:

Definition: A marinarius (pronounced mar-nair-ee-us) is a seaman or mariner. In historical legal Latin, marinarius capitaneus referred to the admiral or warden of the ports.

Examples: A sailor on a ship is a marinarius. In ancient times, the marinarius capitaneus was responsible for overseeing the ports and ensuring the safety of ships and their crews.

Explanation: The term marinarius is used to describe someone who works on a ship or is involved in sea navigation. The example of a sailor on a ship illustrates this definition. The historical example of marinarius capitaneus shows how the term was used in ancient times to refer to a specific role in the management of ports and ships.