Many people get scared when they see a spider run across the floor of their home. Girls scream when they see them. Some men run away. Of course, most people do not really like spider, but we are not obsessively afraid of them either. But some people have an unreasonable fear of spider. The scientific name for this is called areahnophobia. The word comes from the Greek word arachne,which means spider. Phobia means fear. For many people,this fear is an obsession.