[1] Common types of geometries include points, arcs, and polygons.
The definition of features that share membership of a common theme is a feature type, though there are a number of terms for this characteristic, including category, feature class, group, layer, level, object, and theme.
Data modelers can use feature types to create a hierarchical structure.
[2] For example, a dataset may consist of types called highways, streets and lanes.
The system may group these particular types together under a category called "Roads".