A more thorough explanation:

Definition: Ex parte materna is a Latin term that refers to something that is related to the maternal line or on the mother's side.

Example: If someone says, "My grandmother's ex parte materna was from Italy," it means that their grandmother's ancestors on her mother's side were from Italy.

Explanation: The example illustrates how the term ex parte materna is used to describe a person's ancestry on their mother's side. In this case, the person's grandmother's ancestors were from Italy, and this information is being conveyed by using the term ex parte materna.