The word mariachi was borrowed sometime in the mid-twentieth century from Mexican Spanish, and beyond that the origin is uncertain. For a while, the going theory was that it was borrowed from the French word for "marriage", mariage, because the music was often played at weddings, but that's fallen somewhat out of favor with etymologists because of attestations from before the French invasion of Mexico. It's also been suggested that it may be from an Uto-Aztecan word for the type of wood that traditional dancing platforms were made from, or that it may be an alteration of a woman's name, Maria H, or that it's from a tree name in another, extinct indigenous language. According to Google NGrams, literary usage of the word mariachi peaked in 2003 and has been declining since.
Adam Aleksic is a sophomore studying linguistics and government at Harvard University. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.