A more thorough explanation:

ATAVUNCULUS

Atavunculus is a Latin term used in civil law to refer to a brother of one's great-great-great-grandfather.

For instance, if your great-great-great-grandfather had a brother, that brother would be your atavunculus.

Another example would be if you were researching your family tree and discovered the name of your atavunculus listed in an old document.

The definition of atavunculus is quite specific, referring only to the brother of one's great-great-great-grandfather. The examples provided illustrate how this term might be used in practice, either in a genealogical context or in a legal one.