Glycerin. Glycerin is an ingredient that can be found in many beauty products because of its moisture locking properties. It is a form of sugar alcohol that is available naturally in vegetable oils and can also be the byproduct of soap making.
Definition of wheel and axle : a mechanical device consisting of a grooved wheel turned by a cord or chain with a rigidly attached axle (as for winding up a weight) together with the supporting standards
Many people use term wheel as a rim meaning the entire metal part to which the tire is mounted because rim and wheel are usually cast or pressed from a single piece of metal. The main difference between wheel and rim is that rim is not the whole wheel but only a part of the wheel. Key parts of the wheel are rim and disc. The hub may be also considered as a part of the wheel. The hub is wheel base with studs on which the wheel is attached to the suspension.