The term shortening generically refers to any baking fat that's solid at room temperature, like butter and margarine. But more often, it describes a semi-solid fat made from hydrogenated vegetable oil that's used in baking to achieve a "short," or flaky, texture.
By adding hydrogen gas to vegetable oil at a high pressure and temperature, the flavorless substance goes from being a liquid to a solid at room temperature.
Although shortening has fallen out of favor in recent years because it contains trans fat, the ingredient remains a staple around the world for many reasons. It has a higher smoke point than butter or margarine, meaning it won't burn in a sauté pan. It also requires no refrigeration, and can lengthen the shelf life of baked goods. What do you use shortening for?
Source: Flickr User VirtualErn