Think about talent or potential. People used to be hired for that. Further down the curve is skills. Maybe you really can do something now. Still further down is competency.
People try to test for that or build job descriptions around that.
It's like four stops on a train track. For a systems person the second stop might be knowing Lotus Notes. The third would be proficiency in several suites of software applications. When you reach capacity you can understand software packages quickly. Today to be world class at Lotus Notes doesn't guarantee you anything.