It's Ottoman - an upholstered often overstuffed seat or couch usually without a back.
Ottoman introduced into Europe in the late 18th century from Turkey, where, piled with cushions, it was the central piece of domestic seating.
One of the early versions was designed as a piece of fitted furniture to go entirely around three walls of a room, and from this evolved a smaller version, designed to fit the corner of a room.
As the 19th century progressed, ottomans became circular or octagonal, either with arms radiating from the center, which divided the seating space into sections, or with a central, padded column, which often supported a plant or statue and against which one could lean.
Ottomans and footstools became synonymous -- a footstool being a low upholstered stool with legs, originally set next to a hearth.
When the ottoman isn't a seat, it's a table. Toss a few magazines on it -- it's a coffee table. An onyx chessboard turns it into a chess table. A large, tufted cushion, upholstered in kilim carpet, holds an enameled tray with cups, saucers, coffeepot, croissants and a spray or orchids in a slim vase for casual brunch.
Know more about this piece of furniture including its design history, shapes and functions on SFGate.com.