boundarybound‧a‧ry /ˈbaʊndəri/ ●●○ noun (plural boundaries) 🔊 🔊 1EDGE[countable] the real or imaginary line that marks the edge of a state, country etc, or the edge of an area of land that belongs to someoneboundary between 🔊 The Mississippi River forms a natural boundary between Iowa and Illinois. 🔊 National boundaries are becoming increasingly meaningless in the global economy. 🔊 We would need their agreement to build outside the city boundary. 🔊 The stream curves round to mark the boundary of his property. 🔊 Anything that crosses the boundary of a black hole cannot get back. 🔊 We walked through the churchyard towards the boundary wall. 🔊 The property’s boundary line is 25 feet from the back of the house. 🔊 boundary disputes between neighbouring countries► see thesaurus at border2LIMIT[countable usually plural]LIMIT the limit of what is acceptable or thought to be possibleboundary of 🔊 the boundaries of human knowledgewithin/beyond the boundaries of something 🔊 within the boundaries of the lawpush back the boundaries (of something) (=to make a new discovery, work of art etc that is very different from what people have known before, and that changes the way they think) 🔊 art that pushes back the boundaries3BETWEEN FEELINGS/QUALITIES ETC[countable]LIMIT the point at which one feeling, idea, quality etc stops and another startsboundary of/between 🔊 the boundaries between work and play 🔊 the blurring of the boundaries between high and popular culture4CRICKET[countable]DSC the outer limit of the playing area in cricket, or a shot that sends the ball across this limit for extra pointsCOLLOCATIONSADJECTIVES/NOUN + boundary national/state boundaries (=boundaries between countries or states)Big companies usually aim to expand outside national boundaries.international boundaries (=boundaries between countries all over the world)About 10% of hazardous waste is shipped across international boundaries.a city boundaryThe new housing estates stretch beyond the old city boundaries.the northern/southern etc boundary (=of an area or city)the southern boundary of San Franciscoa geographical boundaryToday satellite communications cross all geographical boundaries.a political boundaryReforms could extend the geographical and political boundaries of the EU.a natural boundary (=a river, line of mountains etc that form a boundary)Here, the Andes form a natural boundary between Argentina and Chile.verbsmark/form a boundaryThe river Jordan marks the boundary between Israel and Jordan.cross/transcend a boundaryThese are practical problems that cross political boundaries.boundary + NOUNa boundary wall/fenceThe boundary wall was about twenty foot high.a boundary lineThere was some disagreement about the exact position of the boundary line.a boundary dispute (=a disagreement about where a boundary should be, for example between neighbours)We had to hire a lawyer to sort out the boundary dispute.