The preceding answer is essentially correct, except that the 'Shortening' is hydrogenated vegetable fats. It can be sunflower oil, cottonseed oil or any number of 'vegetable' derived oils. The hydrogenation means the product is semi-solid rather than liquid.
Probably the most popular brand here in the U.S. is Crisco... it's been around for years. The product is flavorless and is a substitute for lard, butter or other such products, especially in making pastries or pie shells. There has been controvesy about the product's health benefits since the hydrogenation process's trans fats can be a concern. The process, as mentioned, is intended to make the shortening stay firm, even at room temperatures.
I, personally, try to avoid any with Palm Oil listed as an ingredient. I see a brand name of Cookeen listed in the U.K.
Best of luck!