Reflecting the cultures that settled North America, the roots of old-time music are in the traditional musics of the British Isles (primarily English and Scottish) and Ireland. In some regions French and German sources are also prominent. While many dance tunes and ballads can be traced to European sources, many others are of purely North American origin.
The term “old-time”
With its origins in traditional music of Europe and Africa, old-time music represents perhaps the oldest form of North American traditional music other than Native American music, and thus the term “old-time” is an appropriate one. As a label, however, it dates back only to 1923.
Fiddlin’ John Carson made some of the first commercial recordings of traditional American country music for the Okeh label. The recordings became hits. Okeh, which had previously coined the terms “hillbilly music” to describe Appalachian and Southern fiddle-based and religious music and “race recording” to describe the music of African American recording artists, began using “old-time music” as a term to describe the music made by artists of Carson’s style. The term thus originated as a euphemism, but proved a suitable replacement for other terms that were considered disparaging by many inhabitants of these regions. It remains the term preferred by performers and listeners of the music. It is sometimes referred to as “old-timey” or “mountain music” by long-time practitioners.
more here: http://en.wikipedia.org/wiki/Old-time_music