Tin Pan Alley

Etymology
Purported to be a reference to the constant sound of pianos as songwriters worked out their tunes.

Proper noun

 * 1) The district in New York City centered on 28th Street from the late 19th to the early 20th century, wherein thousands of popular songs were commercially written.
 * 2)  The songwriting and publishing industry which was built around the songs produced in Tin Pan Alley; the style of popular music produced by this industry.