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[boun-duh-ree, -dree] /ˈbaʊn də ri, -dri/
noun, plural boundaries.
something that indicates bounds or limits; a limiting or bounding line.
Also called frontier. Mathematics. the collection of all points of a given set having the property that every neighborhood of each point contains points in the set and in the complement of the set.
Cricket. a hit in which the ball reaches or crosses the boundary line of the field on one or more bounces, counting four runs for the batsman.
Compare six (def 5).
Origin of boundary
First recorded in 1620-30; bound3 + -ary
Related forms
transboundary, adjective
Can be confused
boundary, limit, parameter, variable.
Synonym Study
1. Boundary, border, frontier share the sense of that which divides one entity or political unit from another. Boundary, in reference to a country, city, state, territory, or the like, most often designates a line on a map: boundaries are shown in red. Occasionally, it also refers to a physical feature that marks the agreed-upon line separating two political units: The Niagara River forms part of the boundary between the United States and Canada. Border is more often used than boundary in direct reference to a political dividing line; it may also refer to the region (of, for instance, a country) adjoining the actual line of demarcation: crossing the Mexican border; border towns along the Rio Grande. Frontier may refer to a political dividing line: crossed the Spanish frontier on Tuesday. It may also denote or describe the portion of a country adjoining its border with another country (towns in the Polish frontier) or, especially in North America, the most remote settled or occupied parts of a country: the frontier towns of the Great Plains. Frontier, especially in the plural, also refers to the most advanced or newest activities in an area of knowledge or practice: the frontiers of nuclear medicine. Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for boundaries
Contemporary Examples
Historical Examples
  • Boys were flogged at boundaries, to impress the boundaries on their memory.

  • Monks also erected crosses to mark the boundaries of the property of their monastery.

    English Villages P. H. Ditchfield
  • Arthur pursued the path which would take him round the cathedral to the boundaries.

    The Channings Mrs. Henry Wood
  • The parties could agree neither on terms of consolidation nor on boundaries.

  • Never did he set his foot beyond the boundaries of his garden.

British Dictionary definitions for boundaries


/ˈbaʊndərɪ; -drɪ/
noun (pl) -ries
something that indicates the farthest limit, as of an area; border
  1. the marked limit of the playing area
  2. a stroke that hits the ball beyond this limit
  3. the four runs scored with such a stroke, or the six runs if the ball crosses the boundary without touching the ground
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for boundaries



1620s, from bound (n.) + -ary.

Online Etymology Dictionary, © 2010 Douglas Harper
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