A carpet is a thick, woven floor covering. Most carpets cover the whole floor in a room, as opposed to a rug, which only covers a small section.
Carpets are made from polyester fibers, or wool, or nylon — most often, these soft materials are loops or strings that form the carpet's "pile," and are attached to a solid backing. A carpet can be very densely woven and flat, or it can be tufted and thick. To carpet means to cover something as if with a carpet: "Then the snow carpets the ground, and winter is here."