c. 1400, frowntere, "front line of an army;" early 15c., fronture, "borderland, part of a country which faces another," from Old French frontiere "boundary-line of a country," also "frontier fortress; front rank of an army" (13c.), noun use of adjective frontier "facing, neighboring," from front "brow" (see front (n.)). In reference to North America, "part of the country which is at the edge of its settled regions" from 1670s. Later it was given 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]
实用例句
1. A "frontier-free" Europe implies a greatly increased market for all economic operators.
“无国界的”欧洲对所有经营者来说都意味着一个大大扩展了的市场。
来自柯林斯例句
2. Until very recently Texas was an unsettled frontier.
就在没多久之前，得克萨斯州还是一个荒无人烟的边远地区。
来自柯林斯例句
3. the frontier between the land of the Saxons and that of the Danes
撒克逊人土地和古斯堪的纳维亚人土地的边界
来自《权威词典》
4. There were very few border controls on the southwestern frontier.
西南国界上没几个边境检查站.
来自《简明英汉词典》
5. The frontier station was starved for food and water.
