All of the above - technically. Shortening, in its most generic meaning, is any fat or oil that is used to make a short crust or dough (one that has a high ratio of fat to flour, and turns out tender, crumbly, and rich).

In general usage, when you see the word shortening as an ingredient in a recipe in this country, the author is referring to solid vegetable shortening, of which Crisco is the leading brand.