Agoraphobia is a form of anxiety disorder, the abnormal fear of expecting or experiencing a difficult or embarrassing situation from which the sufferer cannot find an escape.
The word is an English adoption of the Greek words agora (αγορ?) and phobos (φ?βος). Literally translated in modern Greek as "a fear of the marketplace".
This translation is the reason of the common misconception that agoraphobia is a fear of open spaces. This is most often not the case since people suffering from agoraphobia usually are not afraid of the open spaces themselves, but of public spaces or of situations where a person is afraid of having a panic attack and will not be able to receive help.
Another misconception is that agoraphobia is a fear of "crowded spaces" (which would be the social anxiety disorder). Once again, an agoraphobic does not fear people: he or she rather fears an embarrassing situation with no escape. Some people with agoraphobia are comfortable seeing visitors, but only in a defined space they feel in control of. Such people may live for years without leaving their homes, while happily seeing visitors and working, as long as they can stay within their safety zones.
An agoraphobic may experience severe panic attacks in situations where they feel trapped, insecure, out of control, or too far from his personal comfort zone. During severe bouts of anxiety, the agoraphobic is confined not only to their home, but to one or two rooms and they may even become bed-bound until their over-stimulated nervous system can quiet down, and their adrenaline levels can return to a more normal level.
Agoraphobics are often extremely sensitized to their own bodily sensations, subconsciously over-reacting to perfectly normal events. To take one example, the exertion involved in climbing a flight of stairs may be the cause for a full-blown panic attack, because it increases the heartbeat and breathing rate, which the agoraphobic interprets as the start of a panic attack instead of a normal fluctuation.
People with severe agoraphobia develop the ability to avoid situations that may bring on an attack.