classical music from the 20th century is extremely varied. there are lots of different “schools” (meaning: ways of thinking) as lots of composers had their own ideas about how to compose in ways that were different from what had been done before. a lot of these genres (types of music) had names ending in “ism”: there was serialism, expressionism, neoclassicism, impressionism as well as jazz, world music (music from non-european cultures) and folksong and, later on electronic music and then minimalism and even post-modernism.