Coupling refers to the degree of interdependence between modules. A high degree of coupling indicates that a change in one module is likely to result in changes in other modules. Cohesion, on the other hand, refers to the degree to which the elements inside a module are related to each other. A highly cohesive module is one where all the elements are closely related to each other and work together to achieve a common goal. In general, it is desirable to have low coupling and high cohesion. This means that modules should be independent of each other and that the elements inside a module should be tightly integrated.