A coverage is a georelational data model that stores vector data—it contains both the spatial (location) and attribute (descriptive) data for geographic features. Coverages use a set of feature classes to represent geographic features. Each feature class stores a set of points, lines (arcs), polygons, or annotation (text). Coverages can have topology, which determines the relationships between features.
A coverage is stored as a directory within which each feature class is stored as a set of files. For example, a coverage appears in ArcCatalog with the icons as shown below. In this example, you can see that the streams coverage is a line coverage containing an arc (line) file, annotation for the line, and a tic file. There are also two versions of coverage files.