Definition: An object is chiral if it is not identical to its mirror object. Object and nonidentical mirror object are called enantiomorphic.

Many objects are identical to their mirror object, they a achiral ("not handed").

What is true for any objects is of course true also for molecules: A molecule and therefore a compound may be chiral or achiral. A chiral molecule (compound) and its mirror image are called enantiomers or enantiomeric. Enantiomers are a special kind of stereoisomers.

Under certain conditions chiral molecules (compounds) differ in their properties from achiral ones, and two enantiomers differ in their properties from one another. Such properties may be certain physical quantities, but also chemical reactivity, biological activity including pharmaceutical activity or toxicity. For that reason any chemist, biochemist, biologist, pharmacist, biotechnologist, etc., should be familiar with the phenomenon of chirality.