Definition of "Formosan"

The great Jesuit missionary, St. Francis Xavier, also spent some time at Öita, and Otomo, its lord, was the first Daimio to embrace Christianity. Still farther south, and in line with these, stretches the chain of the Liuchiu islands, the westernmost of the group lying within 50 miles of the Formosan coast.

1905, Archibald Little, “The Island Empire: Japan”, in The Far East‎, Oxford: Clarendon Press, page 283

From his base at Amoy the Emperor Kanghi dispatched a fleet of 600 junks against Formosa. In two naval battles, on July 1 and 7, 1683, they defeated the Formosans, and occupied Penghu, one of the Pescadores Islands, forming the key of Taiwan.

1926, Hosea Ballou Morse, The Chronicles of the East India Company trading to China‎, volume 1, Clarendon Press, page 48