We don't have synonyms for antillia yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are mantilla, tantilla and anticlia.
(n) :
A phantom island, originating from an Iberian legend, that during 714 AD and the 15th-century age of exploration was said to lie in the Atlantic Ocean, far to the west of Portugal and Spain.
(n) :
A phantom island, originating from an Iberian legend, that during 714 AD and the 15th-century age of exploration was said to lie in the Atlantic Ocean, far to the west of Portugal and Spain.