While it is generally understood to be a fear of open spaces, agoraphobia is a much more complex fear.
It is a serious anxiety disorder than can trap people in their homes or make leading a normal life next to impossible.
Some people with agoraphobia avoid specific places or venues.
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What are you most afraid of?
There are many things that we are fearful of, but here are the ten most common phobias:
Social phobias are the most common type of fear.
Up to one in 20 people have a social phobia.
Some people fear heights so badly the escalators at the local shopping centre give them vertigo.
Vertigo is different to the phobia and is the sense of dizziness people can develop.
For others a cliff-top lookout or a tall building makes their head spin.
With all the media coverage of air disasters it is understandable many fear being in a plane crash and hence have a fear of flying.
But with more than 100,000 commercial flights around the world each day, the chances of being struck by lightning are higher than dying in a plane crash.
Sometimes the fear of flying is actually more closely linked to a fear of enclosed spaces.
People with this fear say they feel like the walls are closing on them.
Some theories suggest there is a genetic link to specific phobias as a kind of dormant survival mechanism.
They are small, they crawl and they often bite, so it is understandable why many people do not like spiders and insects.
But they are a crucial link in the food chain and we cannot live without them.
Indiana Jones famously quipped "I hate snakes", and he is not alone.
A fear of all things long and venomous is common to many.
The great thing about snakes is that if you leave them alone they will leave you alone.
A fear of dogs is a common phobia, particularly among children and door-to-door sales agents.
The fear can be exacerbated by a negative experience with an animal and can be one of the most difficult phobias to conquer given canines can sense people's fear.
It is understandable why the booming sound of thunder can send people's hearts racing and a fear of storms is common.
Realistically it is lightning that can hurt people, but the chance of that happening is remote.
Having a sharp piece of metal stuck in your arm is always an unpleasant thought and many people develop a strong aversion to needles.
But needles are typically worth the pain with them either delivering vaccinations, delivering blood donations or helping to investigate a potential illness — even creating a tattoo.