Obolus \Ob"o*lus\, n.;pl. {Oboli}. [L., fr Gr. (?)] (Gr.Antiq.) (a) A small silver coin of Athens, the sixth part of a drachma, about three cents in value. (b) An ancient weight, the sixth part of a drachm.
obolus n : a Greek unit of weight equal to one tenth of a gram [also: {oboli} (pl)]