congius

Etymology

From Latin congius, from Ancient Greek κογχίον (konkhíon), from κόγχη (kónkhē) and κόγχος (kónkhos, “mussel shell”) + -ίον (-íon, “-y: forming diminutives”).

noun

1. (historical) A Roman unit of liquid measure reckoned as the volume of 10 Roman pounds of wine and equivalent to about 3.3 L although differing slightly over time.
2. (historical) A Roman unit of mass instituted by Vespasian equivalent to about 3.3 kg, the weight of a congius of water.