1. a physical structure that blocks or prevents movement or access
2. something that prevents progress, communication, or understanding

Examples

• The concrete barrier separated the highway lanes.
• Police set up barriers to control the crowd.
• Language can be a barrier to effective communication.
• She broke through the barrier of fear to achieve her goals.
• The Great Barrier Reef is a natural wonder.
• Economic barriers prevent many students from attending college.
• The sound barrier was first broken in 1947.