ESRI Shapefile is a simple, non-topological format for storing the geometric location and attribute information of geographic features. A Shapefile is one of the spatial data formats that can be utilised in ArcGIS.
The Shapefile format defines the geometry and attributes of geographically referenced features in as many as six files with specific file extensions that should be stored in the same project workspace.
They are:
.shp – the file that stores the feature geometry.
.shx – the file that stores the index of the feature geometry.
.dbf – the dBASE file that stores the attribute information of features.
.prj – the projection file that provides the information on the coordinate reference system.*
.sbn and .sbx – the files that store the spatial index of the features.**
*When a Shapefile is added as a theme to a view, this file is displayed as a feature table.
**These two files will only exist if you perform theme on theme selection, spatial joins, or create an index on a theme's SHAPE field.
The shapefile has two attributes (FID and SHAPE) that are virtual columns created by ArcGIS when accessing the table contents but are not visible in the attribute table. The FID column uniquely identifies each object stored in the table. The SHAPE column provides information about the feature geometry.