What does deck mount and wall mount mean on a tub?

Deck mount and wall mount refer to tub filler installation types. Deck mount tub fillers are intended to be secured in a tub that has pre-drilled designated holes on the top of the tub. Wall mount tub fillers vary by model. Some are intended to attached to a tub that has pre-drilled holes on the wall of the tub while other wall mount tub fillers have a long enough spout to mount directly to a wall near the tub.