| Noun | 1. | horizontal surface - a flat surface at right angles to a plumb line; "park the car on the level" floor, flooring - the inside lower horizontal surface (as of a room, hallway, tent, or other structure); "they needed rugs to cover the bare floors"; "we spread our sleeping bags on the dry floor of the tent" paved surface - a level horizontal surface covered with paving material platform - a raised horizontal surface; "the speaker mounted the platform" surface - the outer boundary of an artifact or a material layer constituting or resembling such a boundary; "there is a special cleaner for these surfaces"; "the cloth had a pattern of red dots on a white surface" |