This .NET class wraps the AcBrElement ObjectARX class. 

The Element class is the interface base class for mesh elements. This class defines the functions that are common to all dimensions of mesh elements, and cannot be directly set by the user as the initialization requirements are only available internally. An element is a minimal closed, ordered subset of connected nodes in a mesh. 

Autodesk.AutoCAD.BoundaryRepresentation.MeshEntity
    Autodesk.AutoCAD.BoundaryRepresentation.Element
        Autodesk.AutoCAD.BoundaryRepresentation.Element2d

Public abstract Class Element
Inherits MeshEntity

public abstract class Element : MeshEntity;