That is, if every space a hydrogen atom could occupy, by the rules of chemistry, is filled with a hydrogen atom, then the fatty acid is saturated. If there's space for one more hydrogen atom somewhere along the chain, it's a monounsaturated fatty acid. Fats and oils earn their labels by the proportion of the different kinds of fatty acids they contain. A saturated fat has mostly saturated fatty acids, a polyunsaturated fat is predominantly made up of polyunsaturated fatty acids, and monounsaturated fats consist mostly of monounsaturated fatty acids. The last two kinds of fats we'd probably usually think of as oils, because the more saturated a fat is, the more likely it is to be solid at room temperature.
Unsaturated fats are naturally liquid.
There are exceptions to this convenient rule of thumb, of course. However, the label also states that shortening is hydrogenated. That means hydrogen gas has been bubbled through the oils. Once again, it's all in the hydrogen. It's filled the spaces available along the carbon chains, this time with the help of technology rather than nature.