Fatty acids with more than one double bond.
Note: The double bonds usually have cis (Z) configuration and are methylene-interrupted.
Example: linoleic and arachidonic acids.
Source:
PAC, 2018, 90, 1121. 'Terminology of bioanalytical methods (IUPAC Recommendations 2018)' on page 1181 (https://doi.org/10.1515/pac-2016-1120)