A more thorough explanation:

Definition: Duellum is a historical term that refers to a trial by combat. It comes from the Latin word "duo," which means "two."

Example: In medieval Europe, duellum was a common way to settle disputes between two parties. For example, if two knights had a disagreement over land ownership, they might engage in a duel to determine who was the rightful owner.

Explanation: The example illustrates how duellum was used as a form of trial by combat. In this case, the two knights fought each other to determine who had the right to the land. The winner of the duel was considered to be the rightful owner, and the loser had to accept the outcome.