1. (n.) A region near a border or beyond settled lands\; that part of a country which fronts or faces another country or an unsettled region; the marches; the border, confine, or extreme part of a country, bordering on another country; the border of the settled and cultivated part of a country; as, the frontier of civilization.

2. (n.) An outwork.

3. (a.) Lying on the exterior part; bordering; conterminous; as, a frontier town.

4. (a.) of or relating to a frontier.

5. (v. i.) To constitute or form a frontier; to have a frontier; -- with on.

Berlin wall China Darkest Africa God knows where Greenland North Pole Outer Mongolia Pago Pago Pillars of Hercules Siberia South Pole Thule Tierra del Fuego Timbuktu Ultima Thule Yukon anteriority antipodes back country backcountry backwash backwater backwoods bamboo curtain bold front boondock boondocks border border ground border line bordering borderland borderline bound boundary boundary condition boundary line bounding bounds bourn brave face brave front break boundary breakoff point brush bush bush country bushveld ceiling circumscription coastal compass confine cutoff cutoff point dark horse deadline delimitation determinant determinative determining display division line end enigma extreme extremes extremity facade face facet facia finish floor fore forefront foreground forehand foreland forepart forequarter foreside forests foreword fringing front front elevation front line front man front matter front page front view frontage frontal frontier post frontiers of knowledge frontispiece godforsaken place hack head heading hedge high-water mark hinterland interface iron curtain jumping-off place lap limbic limen liminal limit limitation limiting limiting factor limits line line of demarcation littoral low-water mark lower limit march marches marchland marginal mark matter of ignorance mete mystery n nowhere obverse outback outer space outlandish outpost outskirts pale pole preface prefix priority proscenium puzzle remote riddle rimming sealed book skirting start starting line starting point sticks target date term terminal terminal date terminus terra incognita the Great Divide the South Seas the boondocks the bush the incalculable the moon the sticks the strange the tullies the unfamiliar the unknowable the unknown three-mile limit threshold timbers time allotment twelve-mile limit unexplored ground unexplored territory uninhabited region unknown quantity unsettled up-country upper limit virgin land virgin territory wasteland wild West wilderness wilds window dressing woodlands woods x z