There are two types of polishing: Adding a polish to the surface to fill in pits, or removing tarnish and abrasions. Both are a way to provide care for an object to extend its life and improve its performance.
The first type of polishing typically uses a compound containing wax and thus the terms may be used interchangeably. This polishing compound is rubbed into the surface until it is built up to a smooth level. This is the typical way to polish cars, surfboards, shoes, furniture and floors. This removes friction as well as adding a shine.
The second type of polishing involves a slight abrasive, sometimes in combination with a wax or other filler. This is most often used on metal objects like silverware, cookware or automobiles. Typically this just results in increased shine.