A molecule or ion is said to be chiral in chemistry if it cannot be superposed on its mirror counterpart by any combination of rotations, translations, and conformational modifications. This geometric characteristic is referred to as chirality. The phrases are taken from the Ancient Greek (cheir) word for 'hand,' which is the most common example of an item possessing this attribute. A chiral molecule or ion has two stereoisomers that are mirror copies of each other; they are generally identified as "right-handed" or "left-handed" by their absolute configuration or some other criterion. Except when interacting with other chiral molecules, the two enantiomers share the identical chemical characteristics. They share the same physical qualities as well, except that they frequently exhibit opposing optical activity.