A product labelled vegetable oil will usually be a blend of oils obtained from, for example, corn, cottonseed, rape seed, sunflower, soyabeans, peanuts or safflower seeds. Unblended vegetable oils will be known by the name of their source, for example cornoil or sunflower oil.
Vegetable Oil is a generic term. Take the seeds of the rape plant, sunflower seeds, soya beans, corn, avocado kernels, nuts and crush to extract the oil. The fruit of the palm plant grown in equatorial areas of the world gives us palm oil and palm kernal oil which is refined into various formats by partially hardening (hydrogenation). Most "vegetable oil" in the uk is rapeseed oil.