Top 40
（重定向自Top Forty）
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.