frontier
['frʌntjə]
n. 前沿；边界；国境
adj. 边界的；开拓的
参考例子
1.The village straddles the frontier.
这村庄横跨边境线。
2.This is a novel about frontier in the United States.
这是一部描写美国边界居民生活的小说。
3.To settlers on the frontier, Jackson was already well known.
对移居者在边境，杰克逊已经是知名的。
英文解释
n.
1.a wilderness at the edge of a settled area of a country
2.an international boundary or the area (often fortified) immediately inside the boundary
3.an undeveloped field of study; a topic inviting research and development
网络释义
frontier
边境; 前沿，新领域; 国境; 境界;
Frontier Airlines
边疆航空公司; 边疆航空; 边境航空公司; 边境航空;
frontier orbital
前沿轨道; 前沿轨域 前沿轨道; 限界轨域; 前沿轨域;
frontier education
边疆教育; 国防教育; 边疆教育 教育 课程;
customs frontier
关境; 关税国境; 海关边界; 关境,关税国境;