The term for the fear of empty spaces is "agoraphobia." This anxiety disorder involves the intense fear of being in situations where escape might be difficult or help unavailable, often leading to avoidance of open or public spaces. People with agoraphobia may feel anxious in crowded areas, on public transportation, or even when leaving their homes. It can significantly impact daily life, and treatment often includes therapy and medication to help manage symptoms, allowing individuals to gradually confront their fears and reclaim their independence.