20th-century classical music
The names of periods in history were usually given to them many years afterwards. For example, the term Middle Ages was not used until long after the Middle Ages had finished. It is difficult to know what to call the period we live in now. In music people often talk about “Modern Music” meaning any music written after 1900. We also talk about “Contemporary Music” meaning more or less the same thing (“contemporary” means “things that are happening in our time”, i.e. “living composers”). Now that the 21st century has started some musicians are starting to talk about “20th century music” (1900-2000) and a period called “Contemporary Music” (1975-today).