Main Entry: Di·phyl·lo·both·ri·um Pronunciation: -'bäth-rE-&m Function: noun : a large genus of tapeworms that isthe type genus of the family Diphyllobothriidae and that comprises a number of parasites of fish-eating birds and mammals including the common fish tapeworm (D. latum) of humans —compareBOTHRIOCEPHALUS