byssum Save Could not find byssi in Logeion dictionaries. byssi Noun: neuter genitive singular of byssum byssi Noun: feminine vocative plural, Noun: feminine genitive singular, Noun: feminine nominative plural of byssus See byssi in Morpho Gaffiot 2016 byssum, ī, n. , Isid. Orig. 19, 27, 4, v. le suivant.