Salsa is both a type of tomato sauce and a type of dance, and both definitions come from the Latin word for "salt", sal. That word later evolved into salsus, which meant "salted". Many sauces are salted, so it's not that surprising that salsus became the Spanish word salsa, which was brought into English in the year 1846. And since salsa is made of many mixed ingredients, and the salsa dance is a mix of different types of dance (jazz, rock, and general Latin music), it makes sense that the word would further be applied to name the dance in 1975. That second meaning must have been much more popular; usage increased almost 50 times over from 1974 to 2000. This was a really interesting series of transitions, but let's go back to the Latin word sal. This has a simple origin; it comes from Proto-Indo-European root sehls, with the same meaning.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.