hybridized carbon atoms, and one or several functional groups. The functional group
is an atom, or a group of atoms that has similar chemical properties whenever it occurs
in different compounds. It defines the characteristic physical and chemical properties
of families of organic compounds.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1116