frontier

邊界、國界、邊境

They were stopped for questioning at the frontier between the two countries.

他們在兩國邊界被攔下來盤查。

邊疆、邊地

Life on the frontier was harsh, and settlers relied on each other.

邊疆的生活十分艱苦，墾荒者只能互相扶持。

前沿、新領域、尖端常用複數

Gene editing has opened up new frontiers in medicine.

基因編輯為醫學開拓了新的前沿領域。

邊境的、邊疆的

The museum recreates a frontier town from the nineteenth century.

這座博物館重現了十九世紀的邊疆小鎮。