frontier
UK: ˈfrʌntɪə | US: frʌnˈtɪr
n. 1. A border separating two countries or regions.
n. 2. The extreme limit of settled land beyond which lies wilderness.
n. 3. A new field of knowledge or activity (figurative).
The word "frontier" originates from Old French frontiere, derived from front (forepart, forehead) + the suffix -iere (indicating location or relation). The root front traces back to Latin frons (forehead, front), metaphorically extended to mean "boundary" or "outer edge." The suffix -iere evolved into English -ier, often denoting places or roles (e.g., "frontier" as a border zone). Historically, the term shifted from literal borders (e.g., between nations) to figurative limits (e.g., scientific frontiers).
The pioneers crossed the frontier into uncharted territory.
Canada and the US share the longest undefended frontier in the world.
Space exploration represents the next frontier for human discovery.
The novel explores the frontiers of artificial intelligence ethics.
Settlers faced harsh conditions on the western frontier.