Английский Этимологический словарь - public

- 14c., from L. publicus, altered (by influence of L. pubes "adult population, adult") from Old L. poplicus "pertaining to the people," from populus "people." Public relations first recorded 1913; abbreviation P.R. is from 1942. Public school is from 1580, originally, in Britain, a grammar school endowed for the benefit of the public, which mostly have evolved into boarding-schools for the well-to-do. The main modern meaning in U.S., "school (usually free) provided at public expense and run by local authorities," is from 1644.