*unsymmetrical*

a. 1. Wanting in symmetry, or due proportion of parts. [ 1913 Webster ]

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. [ 1913 Webster ]

3. (Chem.) Being without symmetry of chemical structure or relation; as, an unsymmetrical carbon atom. [ 1913 Webster ]

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. [ 1913 Webster ]