'Short' here refers to the crumbly nature of the finished product, as opposed to a 'long' bread, which would be... y'know, normal bread. In this case, that tendency to crumble comes from BUTTER. SO MUCH BUTTER.
The batch of cookies (that I made) in the picture above came out to something like three dozen. There was A POUND of butter in that. Which means each of those cookies had almost a tablespoon of butter in it.
If you're inclined, you can make larger pieces and score them before baking, and break them into bars or wedges (petticoat tails) after they bake. (Some people are fancy; I am not.)
The recipe is stupidly easy - take a pound of butter at a cool room temperature and cream in a cup of (preferably powdered) sugar in a stand mixer, then mix three and a half cups of flour in. (That's it - three ingredients.) The dough is easier (and a lot less messy) to work if it's chilled after it's mixed, so stick it in the fridge for half an hour, and work it on a well floured surface. Personally, I roll the dough into logs and cut rounds from those, leaving room for them to spread on a sheet of parchment, and cook at 350F (175C) for ten minutes or so (until the edges just start to brown). If you go with a thicker shape, you will probably need to adjust your cooking time up to get the dough done all the way through.