noun🔗ShareThe 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." "geographynationareapoliticsstateChat with AIVocabulary GamePractice Reading
noun🔗ShareThe most advanced or recent version of something; leading edge."the frontier of civilization"technologyscienceachievementChat with AIVocabulary GamePractice Reading
noun🔗ShareAn outwork of a fortification."The soldiers patrolled the frontiers of the castle's outer wall, watching for enemy movements. "militaryarchitecturewarChat with AIVocabulary GamePractice Reading
