Blind baking is indeed just baking without a filling — it can be fully or partially. Typically you do this because your filling will either need to bake for a shorter time than your crust (a quiche for example) or not at all (a pie filled with some kind of pre cooked/set custard). It can also be done to help 'set' a crust against a filling that will make it rather soggy.
Oftentimes you will want something neutral in the shell to keep it from becoming a big bubbly, puffed up crust. This may be in the form of formal 'pie weights' or just a piece of parchment paper and some dry beans will suffice.
I have no idea why it's called blind baking, but the English.SE site is notoriously good at word origins.