What part of speech is a frontier?

"Frontier" can be a few different parts of speech, depending on how it's used in a sentence:

* Noun: This is the most common use. It refers to a boundary or edge of a settled area, especially in the past when it was marked by the wilderness.

* Example: "The pioneers crossed the frontier to settle the West."

* Adjective: It can describe something that is on the edge or at the forefront of something, like a new technology or idea.

* Example: "The company is on the frontier of artificial intelligence research."

* Verb: Less common, but it can be used to mean "to establish a frontier."

* Example: "They frontierede the land, pushing back the wilderness."

So, without context, it's impossible to definitively say which part of speech it is.