Definitions

1. noun

a line or area at the edge of a country, region, or area of activity.

“The explorers crossed the frontier into uncharted territory.”

2. noun

a region or area at the edge of a country, region, or area of activity, especially one characterized by lawlessness or violence.

“The lawless frontier towns were notorious for their crime and violence.”

3. noun

a boundary or limit, especially one that is difficult to cross.

“The cultural frontier between the two communities was difficult to navigate.”

4. verb

to be or become the boundary or limit of something.

“The new development will frontier the city’s limits.”