Cohesion
Cohesion is a design principle and a measure of the degree to which the elements inside a module belong together. A module with high cohesion groups elements that are closely related in the business domain. The single responsibility principle is cohesion applied at the class and module level: a module with a single reason to change is, by definition, highly cohesive.
Because modules with high cohesion tend to have fewer dependencies on other modules, highly cohesive systems also tend to be highly modular, with low coupling between components.
Achieving high cohesion requires good domain modeling. When the domain boundaries are not well understood or designed, cohesion tends to be low and coupling tends to be high.
The relationship runs both ways. High cohesion keeps connascence local, so that any strong coupling between elements stays within a single module rather than crossing boundaries. The active counterpart is decoupling, the practice of weakening the coupling that remains between modules.
"High cohesion" is one of the GRASP patterns, an evaluative principle applied alongside the more specific responsibility assignments in that set.