Xavier originated is use as a given name after Saint Francis Xavier, cofounder of the Jesuit order, who got his name from the Spanish-Basque village where he was born. His birthplace was Javier, the name of which was derived from the Basque place name Etxeberria, meaning "castle" or "new house."

Thanks to two cultural influences, January has joined March, April, June and August as a plausible month name.