There are five main definitions of the word triad. In music, it can refer to a chord of three tones; in electronics, it can refer to three phosphor dots on a cathode ray tube; in linguistics, it can be a word with three syllables; and, in general, it can be a group of three things. All four of these just come from the Latin and Greek word for three, trias, which eventually traces to the Proto-Indo-European reconstruction trei, also "three". The fifth definition, referring to organized crime syndicates in east Asia, is also related to the others but it has a much more interesting backstory. The first recorded mention of them in English corpora is from the early nineteenth century, and there are two main theories as to where the name came from. It's been suggested that British authorities in Hong Kong named them after the traditional triangular symbol that they used in a lot of patriotic imagery, but the term is also thought by others to predate British involvement in the area. It could also be a translation of Chinese San Ho Hui, or "triple union society", a secret organization formed to cause the ouster of the Manchu Dynasty - with the name referring to the union of heaven, earth, and man. Either way, throughout the 1800s similar groups proliferated in Chinese and Chinese-influenced areas, retaining the name. Recently, the contemporary usage of the word has also been used by some to refer to Chinese criminal organizations in general, not just ones with that particular tradition.
Hello! I'm Adam Aleksic, a senior studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy trivia, politics, vexillology, geography, board games, conlanging, art history, and law.