Jawbone... that is one theory (which is incorrect... the French inadvertently named Canada after the Native Peoples' word for village - yeah, I know, we are the village people... piss off).

However, re the Portugese, "... Ca nada meaning "Here, there is nothing"?", you should really quote the entire translation which conveys much more meaning..... "Why the fuck would you ever go way ta Jaysus up there ? There's nuthin but skeeters in the summer and snow in the winter. You nuts or somethin?"