Definition
A boundary is where one thing ends and another begins — a line, real or agreed, that separates inside from outside, mine from yours, one field of study from the next. Physical boundaries fence off land; personal boundaries mark what you will and won't accept; disciplinary boundaries divide subjects. The word stresses the dividing edge itself rather than the space it encloses, which is why we speak of 'pushing the boundaries' — moving the very line that decides how far is too far.
Examples
- The river forms a natural boundary between the two countries.
- Every academic boundary is a kind of constraint, useful until a new question refuses to respect it.
- Crossing that boundary felt like stepping over a threshold there was no coming back from.
Collocations
push the boundaries·cross a boundary·a clear boundary·set boundaries·the boundary between
Synonyms
border·limit·edge·perimeter·demarcation
Antonyms
centre·interior
Word family
bound (verb)·boundless (adjective)·bounded (adjective)
In TOEFL & IELTS
A flexible academic noun. Literally it means a border (IELTS maps, geography); figuratively it means a limit (TOEFL lectures on ethics, science, psychology). 'Push the boundaries of' is a strong collocation for essays on progress and innovation. Mind the spelling — bound-a-ry — and the plural boundaries. Distinguish it from 'border' (usually political or physical) when the sense is abstract limits.