diamond problem

Etymology
So called because a diagram of the classes has a diamond (quadrilateral) shape.

Noun

 * 1)  The ambiguity that arises when two classes B and C inherit from A, and a further class D inherits from both B and C, so that if there is a method in A that B and/or C has overridden, and D does not override it, it is unclear which version of the method D should inherit.