From ibikeu Wiki

A typical bike's wheel consists of a hub, spokes, and rim. More simply, it is all the metal bits that turn in order to propel the bike.

There are many different sizes of wheel the designations of which have little bearing on the actual size of the wheel.

The wheel is not to be confused with the tire or rim, although many people do. Please, don't confuse your bike shop's employees, use correct terms.