There is 1) Staining 2) Polishing and 3) Sealing.
1) Staining concrete is applying stains, which may or may not be polished or sealed.
2) Polishing concrete is polishing, which may or may not be stained or sealed.
3) Sealing concrete is applying sealers, which may or may not have been stained or polished.
It might all sound confusing, but for a professionally trained operator, it just means explaining the many options to customers.
The following photos are of stained and sealed concrete, yet not polished. Click on any photo to enlarge. | 
