A more thorough explanation:

Definition: A mensularius (men-suh-lair-ee-uhs) is a person who deals with money, such as a moneychanger or banker. The word comes from the Latin word "mensa," which means "table."

Example: In ancient Rome, a mensularius would exchange coins for people who needed different denominations or currencies. They would also lend money and keep it safe for their clients.

Explanation: The example shows how a mensularius would exchange money for people who needed it. They would also provide other financial services, such as lending money and keeping it safe. This illustrates the definition of a mensularius as someone who deals with money and provides financial services.