When people talk about the days of the Wild West, or American settlers exploring the frontier, they could also use the word “limitrophe.” This term, used as either a noun or an adjective, refers to the borderlands of an area. It comes from a fifth-century Latin word, “limitotrophus,” used for lands set aside for sheltering troops on the outskirts of a settlement. As a noun, “limitrophe” is used in the modern sense to refer to borderlands with a neighboring country. As an adjective, the word might be used to describe such bordering lands, or to designate land on the frontier.