In IUPAC nomenclature, the following subdivision is followed for naming the compounds.

Primary suffixes are used to indicate the degree of unsaturation (i.e., presence of double or triple bonds) in a carbon compound.

e.g.: -ane (for alkanes), -ene (for alkenes), -yne (for alkynes)

Secondary suffixes are those suffixes which describe the main functional group of the compound. They are added after the primary suffix.

e.g.: -one (for ketones), -oic acid (for carboxylic acids)

Example: