Aus·tral Islands 
(ôstrəl) also Tu·bu·a·i Islands (t-bwäē, t′b-ī)
(ôstrəl) also Tu·bu·a·i Islands (t-bwäē, t′b-ī) An island group of southern French Polynesia in the southern Pacific Ocean south of Tahiti. Visited by Capt. James Cook in 1769 and 1777, the islands were annexed by France in 1889.