A more thorough explanation:

Definition: Necessitudo is a Latin word that means "need." In history, it had two meanings:

1. An obligation
2. A close connection or relationship between people, like family

Examples:

• When a knight was given land by a lord, he had a necessitudo to serve and protect the lord.
• Family members have a necessitudo to take care of each other.

The first example shows how necessitudo was used to describe a duty or responsibility. The knight had to fulfill his obligation to the lord who gave him land. The second example shows how necessitudo was used to describe a close relationship between family members. They have a strong connection and a responsibility to take care of each other.