'antillean' originates from the English place-name 'Antilles', ultimately from Spanish 'Antillas' and Portuguese 'Antilhas', which trace back to the Medieval Latin name 'Antilia' (a legendary island).

'Antilia' (Medieval Latin) became Spanish 'Antillas' and Portuguese 'Antilhas' to denote the island group; English adopted the name as 'Antilles', and the adjective/noun 'antillean' developed from that usage.

Initially the term referred to a mythical island ('Antilia') on medieval maps; over time it came to denote the real Caribbean island group (the Antilles), and 'antillean' now means 'of or from the Antilles' or 'a person from the Antilles'.