n.
Pronunciation: ˌ fr ə n- ' tir, ' fr ə n- ˌ , frän- ' , ' frän- ˌ
Function: noun
Etymology: Middle English fronter, from Anglo-French frountere, fronter, from front
Date: 15th century
1 a : a border between two countries b obsolete : a stronghold on a frontier
2 a : a region that forms the margin of settled or developed territory b : the farthermost limits of knowledge or achievement in a particular subject c : a line of division between different or opposed things <the frontier s separating science and the humanities ― R. W. Clark> d : a new field for exploitative or developmental activity
– frontier adjective