Main Entry:

fron·tier

Pronunciation:

\ˌfrən-ˈtir, ˈfrən-ˌ, frän-ˈ, ˈfrän-ˌ\

Function:

noun

Etymology:

Middle English fronter, from Anglo-French frountere, fronter, from front

Date:

15th century

1 a: a border between two countries bobsolete : a stronghold on a frontier2 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 frontiers separating science and the humanities — R. W. Clark> d: a new field for exploitative or developmental activity

— frontier adjective