I'm pretty sure the word "busking" is of British/English origin. I believe someone once posted some documentation to that effect in a Mudcat post (a summary of the word's entymology from the OED, or something like that).

Back when I was doing it (1970-73), the terminology was different, at least in the US. I considered myself a "streetsinger"; I had never heard the word "busker," which is a more inclusive term since it encompasses non-singing performers (and, I suppose, even non-musical performers like mimes, jugglers, etc.) as well as singers.