A more thorough explanation:

Filiolus (fil-ee-oh-ləs) is a Latin word that means "godson." In old records, it was sometimes spelled as "filious."

• When the priest asked who would be the godparents, John proudly volunteered to be his nephew's filiolus.
• The king's filiolus was given a special position in the royal court.

These examples show how filiolus was used to refer to a godson, who was typically a boy. In the first example, John is offering to be the godfather to his nephew, who would then be his filiolus. In the second example, the king's filiolus is given a special role because of his relationship to the king.