If you have an ability that required practice, training, or experience, you have a skill. His welding skill allowed him to create wonderful pieces of art out of metal plumbing pipes. He called his best work "Peace Pipes."
Chess is a game of skill, but Old Maid is a game of luck. The noun skill comes from an Old Norse word, skil, which means distinction. His swimming skills left a lot to be desired: he flailed around in the pool, churning up water like an egg beater. It kept him from drowning, but it didn't look pretty. You're supposed to learn basic math and reading skills in elementary school.