A construction is a spatial arrangement of different geometric shapes. Often the relative positions of the shapes are determined by an algorithmic description, or the arrangement determines another shape implicitly.
For example, incidence relations in projective geometry, shapes determined as intersection of other shapes, or special configurations on other models.
As a guide, meshes should have no holes, no degenerate triangles and elements, no duplicate vertices. Surfaces should have meshes with an adjacency relation.