It is any of a large class of organic compounds including Benzene and compounds that resemble benzene in chemical properties.

Aromatic compounds contain unusually stable ring structures, often made up of six carbon atoms arranged hexagonally. Some of the compounds, however have rings with more or fewer atoms, not necessarily all carbon.

Furan, for example, has a ring with four atoms of carbon and one of oxygen. Also two or more rings can be fused, as in naphthalene.

The characteristic properties of the class, notably the stability of the compounds, derived from the fact that aromatic rings permit the sharing of some electrons by all the atoms of the ring, which increases the strength of the bonds.