Lether Hassock, Hassock Footstool, Moroccan Hassock, Leopard Hassock, Old English Hassock, Storage Hassock, Italian Hassock, etc.

A hassock.

This plaid-patterned upholstered hassock is often used as a footstool.

That matted grass hassock was removed from the bog.

a hassock is a thick cushion used to be sat on or used as a seat

There is no real difference between Hassock and Ottoman. More exactly, a term Ottoman is more common than Hassock. Also, note that there are Hassock Ottomans too. Hassock is more stuffed than Ottoman. In addition, Ottomans have usually storage inside.