Hub caps are decorative covers that fit over the center of a car's wheels. They are used to protect and enhance the appearance of the wheel. Full definition
The new hub cap design is aesthetic and adds to the overall charm of the side profile. (indianautosblog.com)
The other variants will get a 16 - inch wheel while the base model gets hub caps. (overdrive.in)
An alternative is just covering them up with wheel covers (sometimes called hub caps, but wheel covers cover more than the hub). (mechanics.stackexchange.com)