～島
～とう · ～tou · JLPT N2 · noun
island
🏝️ 島 = bird 鳥 + mountain 山: the peak where sea birds land
As a suffix, 島 is read とう in island names and groups: 列島 (rettou, archipelago), 半島 (hantou, peninsula, literally half-island). On its own the word is しま; after another kanji it usually becomes とう.