Let's take the definition from Wikipedia:
The Nashville Sound was pioneered by staff at RCA Records and Columbia Records in Nashville, Tennessee, including manager Steve Sholes, record producers Chet Atkins, Owen Bradley and Bob Ferguson, and recording engineer bill porter. They invented the form by replacing elements of the popular Honky Tonk style (fiddles, steel guitar, nasal lead vocals) with "smooth" elements from 1950s Pop music (string sections, background vocals, crooning lead vocals), and using "slick" production, and pop music structures.
Singers Patsy Cline and Jim Reeves, along with pianist Floyd Cramer, were among the most famous of the artists leading the way to the smooth crooning style of the Nashville Sound's original era.
Through the years, there's been a back-n-forth between the pop and roots camps. …