BOUNDARY definition: 1. a real or imagined line that marks the edge or limit of something: 2. the limit of a subject or…. Learn more. Learn the meaning and usage of the word boundary, as well as related terms such as border, frontier, and limit. Find synonyms, antonyms, and examples from different contexts and domains. The meaning of BOUNDARY is something that indicates or fixes a limit or extent. How to use boundary in a sentence. 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.
