frontier

[fruhn-teer, fron-; also, esp. British, fruhn-teer] /frʌnˈtɪər, frɒn-; also, esp. British, ˈfrʌn tɪər/
noun
1.
the part of a country that borders another country; boundary; border.
2.
the land or territory that forms the furthest extent of a country's settled or inhabited regions.
3.
Often, frontiers.
  1. the limit of knowledge or the most advanced achievement in a particular field:
    the frontiers of physics.
  2. an outer limit in a field of endeavor, especially one in which the opportunities for research and development have not been exploited:
    the frontiers of space exploration.
4.
Mathematics, boundary (def 2).
adjective
5.
of, pertaining to, or located on the frontier:
a frontier town.
Origin
1350-1400; Middle English frounter < Old French frontier, equivalent to front (in the sense of opposite side; see front) + -ier -ier2
Related forms
frontierless, adjective
frontierlike, adjective
semifrontier, noun
transfrontier, adjective
Synonyms
1. See boundary.
Examples from the web for frontier
  • We've got enough aliens and unexplored frontier right here on two-thirds of our pale blue dot.
  • Space is often referred to as the final frontier because it is the last boundary left for humans to discover.
  • frontier markets still represent a small part of the total world equity universe.
  • The final frontier is littered with dead spacecraft and shrapnel.
  • We brought back wolves partly out of nostalgia for the wildness of a long gone frontier.
  • Celebrating the architecture of a changing frontier town.
  • The next frontier will be in less accessible places, such as remote villages, hills and valleys.
  • On the frontier of a frozen ocean, rising temperatures imperil wildlife whose survival depends on ice.
  • The next frontier is a little less common: green walls.
  • The human brain appears to be the last frontier of human evolution.
British Dictionary definitions for frontier

frontier

/ˈfrʌntɪə; frʌnˈtɪə/
noun
1.
  1. the region of a country bordering on another or a line, barrier, etc, marking such a boundary
  2. (as modifier): a frontier post
2.
(US & Canadian)
  1. the edge of the settled area of a country
  2. (as modifier): the frontier spirit
3.
(often pl) the limit of knowledge in a particular field: the frontiers of physics have been pushed back
Word Origin
C14: from Old French frontiere, from front (in the sense: part which is opposite); see front
Word Origin and History for frontier
n.

c.1400, from Old French frontier "prow of a ship, front rank of an army" (13c.), noun use of adjective frontier "facing, neighboring," from front "brow" (see front (n.)).

Originally the front line of an army, sense of "borderland" is first attested early 15c. In reference to North America, from 1670s; 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," 1920]
Frontiersman is from 1782.