An ottoman is a form of couch which usually has a head but no back, though sometimes it has neither. It may have square or semicircular ends, and as a rule it is what upholsterers call “stuffed over” — that is to say no wood is visible.

In American English, an ottoman is a piece of furniture consisting of a padded, upholstered seat or bench, usually having neither a back nor arms, often used as a stool, footstool or, in some cases, as a coffee table. Ottomans are often sold as coordinating furniture with armchairs or gliders. An ottoman can also be known as a footstool, tuffet, hassock, “Sitee” or pouffe. In British English, “ottoman” also denotes an upholstered seat without a back or arms, but one that usually serves as storage, with the seat hinged to form a lid.

Ottomans can be used in many rooms; they can be used in the bedroom, gaming room, family room and guest room. Leather and bench ottomans are used as alternatives to sofas. (source)