We don't have synonyms for francia yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are francoa, francis and franca.
(n) :
(historical) A former kingdom inhabited by the Franks, in Western Europe, spreading over modern-day France (except Brittany and Corsica), the Low Countries, large parts of Germany, Austria, Switzerland, and Northern Italy.
(n) :
(historical) A former kingdom inhabited by the Franks, in Western Europe, spreading over modern-day France (except Brittany and Corsica), the Low Countries, large parts of Germany, Austria, Switzerland, and Northern Italy.