Around 900 BCE, Proto-Polynesian-speaking navigators traveled down to the Tongan archipelago, and from there fanned out to settle a lot of other Pacific islands, such as Hawaii to the north and New Zealand to the south. This led to a bunch of diverse languages like Hawaiian and Maori, with Tongan being the closest to the original Proto-Polynesian. In Tongan, the word Tonga meant "south", because the Tongan islands comprise the southernmost archipelago of central Polynesia. This same word mutated to a spelling of kona and a definition of "leeward" in Hawaiian, which later got applied to the name of an island and a kind of expensive coffee grown in the area. That's a cool connection! Usages of both the words Tonga and Kona have remained relatively constant in recent centuries.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.