In the early 20th century, the Austrian composer Arnold Schoenberg (= beautiful mountain) devised a famous composition system based on giving equal weight to each of the twelve notes of the modern European scale. (He took pairs such as C-sharp and D-flat to be the same note, which they aren’t really, unless you compromise by making them both out of tune; but that’s another story:-). His system was based on sequences or series of notes, which is why we call the result “serial music”. He called the 12-note sequence a “note sequence”, in German a Tonreihe. Unfortunately for every English-speaking music-lover since, this was badly translated as “tone row”, using two false friends.
It’s interesting how “serial music”, which would be a reasonable expression if we were accustomed to “note series”, becomes a lot more opaque when we are used to seeing “tone rows”. Perhaps the original translator – or more likely a musician who was unaware of the issues – was happy to give the phrase a dark, esoteric feel, only for the initiated.
Serial music is also called “12-tone music”, with the same false friend, or “dodecaphonic music” from the Greek word for twelve, perhaps another attempt at making it incomprehensible to ordinary people.