Definition of Filius

Lat. A son; a child. As distinguished from heir, filius is a term of nature, hares a term of law. In the civil law the term was used to denote a child generally. A distinction was sometimes made, in the civil law, between "filii” and "liberi" latter word including grandchildren (nepotes), the former not.

That's the definition of Filius in Black's Law Dictionary 6th Edition. Courtesy of

Official tim editorial.