Call them whatever you like. They have only one compartment and no pockets. Closing them does not result in a neatly folded bag. But it's fine. The two bags are not attached, so you can use one at a time. In fact, we keep one in each of our two homes.

I discovered that strapping my 8-pound lock to the top of my rack gives my bike a shimmy. Tossing it in the pannier does not.