Top 40

Top 40 is a music industry shorthand for the currently most-popular songs in a particular genre. When used without qualification it refers to the best-selling or most frequently broadcast popular music. The term is derived from record music charts, a few of which traditionally consist of a total of 40 songs. Top 40 is also an alternative term for the radio format of such music, also known as Contemporary hit radio.

History

The term "Top 40" for a radio format appeared in 1960. The Top 40, whether surveyed by a radio station or a publication, was a list of songs that shared only the common characteristic of being newly released. Its introduction coincided with a transition from the old ten-inch shellac 78 rpm record format for single "pop" recordings to the seven-inch vinyl 45 rpm format, introduced in 1949, which was outselling it by 1954 and soon replaced it completely. The Top 40 thereafter became a survey of the popularity of 45 rpm singles and their airplay on the radio. Some nationally syndicated radio shows, like American Top 40, featured a countdown of the forty highest ranked songs on a particular music or entertainment publication. Although such publications often listed more than 40 charted hits, such as the Billboard Hot 100, time constraints allowed for the airing of only forty songs; hence, the term "top 40" gradually became part of the vernacular associated with popular music.