Classical music is a broad term that usually refers to music produced in, or rooted in the traditions of Western ecclesiastical and concert music, encompassing a broad period from roughly the 9th century to present times. The central norms of this tradition became codified between 1550 and 1900, which is known as the common practice period. It is still played by many of today's musicians.

When used as a synonym for Western art music, the term encompasses a range of musical styles and approaches, ranging from compositional techniques (such as fugue) to entertaining operettas.

European classical music is largely distinguished from many other non-European and popular musical forms by its system of staff notation, in use since about the 16th century. Western staff notation is used by composers to prescribe to the performer the pitch, speed, meter, individual rhythms and exact execution of a piece of music. This leaves less room for practices, such as improvisation and ad libitum ornamentation, that are frequently heard in non-European art musics (compare Indian classical music and Japanese traditional music), and popular music.

The public taste for and appreciation of formal music of this type waned in the late 1900s in the United States and United Kingdom in particular. Certainly this period has seen classical music falling well behind the immense commercial success of popular music, in the opinion of some, although the number of CDs sold is not indicative of the popularity of classical music.

The term "classical music" did not appear until the early 19th century, in an attempt to "canonize" the period from Johann Sebastian Bach to Beethoven as a golden age. The earliest reference to "classical music" recorded by the Oxford English Dictionary is from about 1836.