About the Castilloux surname
The surname Castilloux has an onomastic interpretation that still needs to be placed in the history of each family line. The form of Castilloux is compatible with French surname tradition. It may derive from an old given name, a place, a nickname, or an occupation; without a documented historical form, choosing a single explanation would be premature. The general meaning of the surname should be distinguished from the history of each family that bears it. The etymological interpretation should be compared with the earliest spellings and places associated with each family line.
Pronunciation:
Kas-ti-jou/kastiju/