An incidence structure is a triple D = (V, B, ) where V and B are any two disjoint sets and  is a binary relation between V and B, that is,  ⊆ V × B.
In the context of combinatorics, an incidence structure is formed by two disjoint sets (V and B) and a relationship that links elements from V to specific points in B, with the constraint that this connection only exists within the bounds of the Cartesian product between V and B.