Cyclic compound
In chemistry, a cyclic compound is a molecule where some atoms are linked together forming a loop or ring. Most of the time, these molecules are organic. There are also many examples of inorganic molecule forming rings.
Cyclic compounds can be aromatic - in this case they are flat. Benzene is a simple aromatic cyclic compound. When they are not aromatic, rings tend not to be flat to avoid steric effects.
Cycloheptane, a non-aromatic cyclic compound.
Benzene, an aromatic cyclic compound.
Cyclic compounds are very important. Many drugs are based on them, like aspirin. There are many reactions that can make or break cyclic compounds. One important class of these is pericyclic reactions.