Aliohatic(Noun) of, relating to, or being an organic compound (as an alkane) and Aromatic of an organic compound : characterized by increased chemical stability resulting from the delocalization of electrons in a ring system (as in benzene) containing usually multiple conjugated double bonds.
basically. aliphatic compounds are carbon compounds which does not contain a benzene ring. while aromatic compounds are carbon compounds which does contains a benzene ring(s). a benzene ring is a compound of carbon atoms arranged in a circle with 3 double bonds.