frontier

American  

[fruhn-teer, fron-, fruhn-teer] / frʌnˈtɪər, frɒn-, ˈfrʌn tɪər /

noun

1. the part of a country that borders another country; boundary; border.

2. the land or territory that forms the furthest extent of a country's settled or inhabited regions.

3. Often frontiers.

   1. the limit of knowledge or the most advanced achievement in a particular field.

      the frontiers of physics.

   2. an outer limit in a field of endeavor, especially one in which the opportunities for research and development have not been exploited.

      the frontiers of space exploration.

4. Mathematics. boundary.

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adjective

1. of, relating to, or located on the frontier.

   a frontier town.

frontier British  

/ frʌnˈtɪə, ˈfrʌntɪə /

noun

1. 1. the region of a country bordering on another or a line, barrier, etc, marking such a boundary

   2. ( as modifier )

      a frontier post

2. 1. the edge of the settled area of a country

   2. ( as modifier )

      the frontier spirit

3. (often plural) the limit of knowledge in a particular field

   the frontiers of physics have been pushed back

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Related Words

See boundary.

Other Word Forms

• frontierless adjective
• frontierlike adjective
• semifrontier noun
• transfrontier adjective

Etymology

Origin of frontier

1350–1400; Middle English frounter < Old French frontier, equivalent to front (in the sense of opposite side; front ) + -ier -ier ²

Example Sentences

Regulators must navigate these frontiers carefully, balancing innovation with ethics.

From The Wall Street Journal

Under the truce, Cambodia and Thailand pledged to cease fire, freeze troop movements and cooperate on demining efforts along their disputed frontier.

From Barron's

The Manus acquisition appears to be Meta’s first major purchase of an AI startup operating an frontier AI model.

From The Wall Street Journal

Alphabet established itself as a household artificial-intelligence name this year as its Gemini frontier model and cloud business grew rapidly.

From MarketWatch

Goods from the frontier—fur, meat, minerals and such—flowed east on the Kansas and Missouri rivers, making KCK the first Kansas City such traders reached.

From The Wall Street Journal