- frontier
- c.1400, from O.Fr. fronter, from front "brow" (see front). Originally the front line of an army, sense of "borderland" is first attested 1413. In reference to N.Amer., from 1676; later with a specific sense:
"What is the frontier? ... In the census reports it is treated as the margin of that settlement which has a density of two or more to the square mile." [F.J. Turner, "The Frontier in American History"]
Frontiersman is from 1782.