This used to confused me when I started living in the States. I went to an English public boarding school, which would have been called a private school in America. Why the opposites? I found a good answer while reading Jeff Jarvis' Public Parts, a book on the impact of sharing and being public in the age of the internet. The definition of Public, prior to the early modern period, was synonymous with the state. Only men of official stature were public. English non state run schools, usually for the privileged, are call public school. Similarly, the common soldiers, the ordinary man without rank, is a private.