Which term describes a fear of being closed in?

Claustrophobia is the term that specifically refers to the fear of being closed in or confined in small spaces. Individuals who experience claustrophobia often feel a sense of panic when they are in tight environments, such as elevators, small rooms, or crowded areas. This condition can trigger physical and emotional responses, leading to avoidance behaviors where a person may go out of their way to avoid scenarios where they might feel trapped.

The other terms listed relate to different types of fears: aerophobia is the fear of flying, agoraphobia is the fear of situations where escape might be difficult or help unavailable, particularly in crowded places or open spaces, and nyctophobia is the fear of darkness. Each of these conditions encapsulates distinct anxieties not associated with being enclosed in small spaces, further emphasizing why claustrophobia is the correct choice for describing the fear of being closed in.