What is "unsymmetrical carbon atom"

Unsymmetrical \Un`sym*met"ric*al\, a.

1. Wanting in symmetry, or due proportion pf parts.

2. (Biol.) Not symmetrical; being without symmetry, as the parts of a flower when similar parts are of different size and shape, or when the parts of successive circles differ in number. See Symmetry.

3. (Chem.) Being without symmetry of chemical structure or relation; as, an unsymmetrical carbon atom.

   Unsymmetrical carbon atom (Chem.), one which is united at once to four different atoms or radicals. This condition usually occasions physical isomerism, with the attendant action on polarized light.