What is "dependencies"

A C element (the client) depends on of an element F (the supplier) if and only if changes in the definition of S can cause changes to F [Martin Fowler].

If the elements are classes, only the direct cause for change (i.e., not through a cascade effect) is called dependence, i.e., the relationship is not transitive.

To packets, C depends on F if a class of C depends on the class in F. Sometimes a transitive occlusion is made, i.e., the dependency of C on a T package can be caused by C depending S depending on T via class dependencies.