what are shapefiles
A shapefile is a simple, nontopological format for storing the geometric location and attribute information of geographic features. Geographic features in a shapefile can be represented by points, lines, or polygons (areas). The workspace containing shapefiles may also contain dBASE tables, which can store additional attributes that can be joined to a shapefile's features. Below is an example of how shapefiles appear in ArcCatalog. You can also see the dBASE file (that may be associated with a shapefile).