Plaster is a smooth paste made of sand, lime, and water which goes hard when it dries. Plaster is used to cover walls and ceilings and is also used to make sculptures.

If you plaster a wall or ceiling, you cover it with a layer of plaster.

If you plaster a surface or a place with posters or pictures, you stick a lot of them all over it.

If you plaster yourself in some kind of sticky substance, you cover yourself in it.

A plaster is a strip of sticky material used for covering small cuts or sores on your body.

If you have a leg or arm in plaster, you have a cover made of plaster of Paris around your leg or arm, in order to protect a broken bone and allow it to mend.