C1noun1K

Boundary

UK /["/ˈbaʊndri/"]/US /["/ˈbaʊndri/"]/

Definition

a real or imagined line that marks the limits or edges of something and separates it from other things or places; a dividing line

In simple words: A line that separates two areas or limits.

Examples

  • The boundary between the two countries is marked by a river.
  • It's important to set a boundary in personal relationships to maintain respect.
  • The researchers proposed a new boundary for climate change thresholds.
  • In sports, crossing the boundary results in a penalty.
  • She felt that her boundary had been violated by her colleague's comments.

Usage notes

Use 'boundary' when discussing physical borders or limits in contexts like geography, relationships, or rules. Avoid using it in very casual conversations.

Grammar pattern

standalone noun

Memory hint

Imagine a 'bound' (limit) around a garden to keep the plants safe.

Collocations

  • common
  • northern
  • southern
  • have
  • form
  • mark
  • fence
  • hedge
  • line
  • across the boundary
  • over the boundary
  • along the boundary

Synonyms

  • border
  • limit
  • margin
  • dividing line
  • perimeter

Antonyms

  • limitless
  • unbounded

Common mistakes

  • Confused with 'boundaries' — learners often forget the plural form.
  • Using 'boundary' in contexts where 'limit' or 'border' is more appropriate.
  • Mixing up the concept with 'barrier', which refers more to an obstruction.