Barrier

Obstacle that prevents or restricts passage or progress.

obstacle blockade fence wall

A barrier is an obstacle that prevents or restricts passage or progress. It can be physical, metaphorical, or conceptual.

/ˈbærɪər/

From Old French barrer 'to bar,' from Vulgar Latin *barrare* 'to shut in with a bar.'

impediment hurdle restraint

obstacle structure

fence wall reef dam

system environment

artificial structure natural object