Biflavonoid and other flavonoid oligomers, which occur widely in nature, are exemplified and named in this recommendation (Flv-3.8).
Source:
PAC, 2018, 90, 1429. 'Nomenclature of flavonoids (IUPAC Recommendations 2017)' on page 1435 (https://doi.org/10.1515/pac-2013-0919)