Cooking oils are sourced from a number of different fruits (olive, avocado, coconut), vegetables (corn), legumes (peanut, soybean), nuts (walnut), and seeds (canola, sunflower). But the recipe for maximizing the freshness and natural flavors of these oils varies, just as it does in the natural world.
Exposure to oxygen, light or heat will subject oil to oxidation, eventually turning it rancid. So in general all oils used for cooking should be sealed tightly and stored away from any heat or sunlight, preferably in a dark pantry and away from appliances.