A futon can be described as a floor mattress, but not all floor mattresses are futons. There are folding mattresses that fold out into a mattress specifically for use on a floor or other flat surface. Technically, any mattress can be used on a floor, although those designed for that function are more suitable. They may have a non-slip bottom, and may also be impervious to fluids and dust. A futon is a flat mat that can be rolled up when not in use.