A plan view is an orthographic projection of a 3-dimensional object from the position of a horizontal plane through the object. In other words, a plan is a section viewed from the top. In such views, the portion of the object above the plane is omitted to reveal what lies beyond. In the case of a floor plan, the roof and upper part of the walls may be left out. Basically, a plan view is just another name for the top view of a 3D object.

A sample floor plan for a single-family home