The term parametric refers to the relationships among all elements of the model that enable the coordination and change management that Vasari provides. These relationships are created either automatically by the software or by you as you work.
In mathematics and mechanical CAD, the numbers or characteristics that define these kinds of relationships are called parameters; hence, the operation of the software is parametric. This capability delivers the fundamental coordination and productivity benefits of Vasari: change anything at any time anywhere in the project, and Vasari coordinates that change through the entire project.
For example, the edge of a mass floor is related to a mass form such that when the face of the mass form is moved, the floor remains connected. In this case, the parameter is one of association or connection.