pee pad

A pad or mat made of absorbent material used as a place for indoor pets to be able to urinate without soiling the floor. The pads may be disposable or reusable, in which case they'd be washable. Pee pads are also used together with litter boxes where the litter box is placed in the middle of the pad and the pad is used to catch anything that might spill out when the box is being used.