Shortening is any fat that is a solid at room temperature and is used to make crumbly pastry and other food products.
The idea of shortening dates back to at least the 18th century, well before the invention of modern, shelf-stable vegetable shortening.[1] In the earlier centuries, lard was the primary ingredient used to shorten dough.[2] The reason it is called shortening is that it makes the resulting food crumbly, or to behave as if it had short fibers. Solid fat prevents cross-linking between gluten molecules. This cross-linking would give dough elasticity, so it could be stretched into longer pieces.[2] In pastries such as cake, which should not be elastic, shortening is used to produce the desired texture.[1][2]