noun🔗Share国境The part of a country which borders or faces another country or unsettled region""The soldiers guarded the country's frontiers against any possible invasion from neighboring nations." "兵士たちは、近隣諸国からの侵略の可能性から国の国境を守った。geographynationareapoliticsstateChat with AIVocabulary GamePractice Reading
noun🔗Share最先端、フロンティアThe most advanced or recent version of something; leading edge."the frontier of civilization"文明の最先端technologyscienceachievementChat with AIVocabulary GamePractice Reading
noun🔗Share前哨基地An outwork of a fortification."The soldiers patrolled the frontiers of the castle's outer wall, watching for enemy movements. "兵士たちは敵の動きを監視しながら、城の外壁の前哨基地をパトロールした。militaryarchitecturewarChat with AIVocabulary GamePractice Reading
