Henry George Liddell, Robert Scott, A Greek-English Lexicon

A.obol, used both as a weight and coin, at Athens, = 1/6 of a δραχμή, rather more than three halfpence, IG12.140.5, al., freq. in Ar., Nu.118, al. ; πολὺ or μικρὸν τοῦ ὀ. a thing of which you get much or little for an obol, i. e. worthless or valuable, Antiph.135, Eup.185, cf. Ar.Eq.945 ; ἐν τοῖν δυοῖν ὀβολοῖν θεωρεῖν 'to sit in the cheap seats', D.18.28.

II. as a weight, Gal.13.295, etc. (ὀβολός, ὀβελός, ὀβελλός, ὀδελός are different dialect forms of a word for 'spit' or 'nail', nails being used in early times as money, six of them making a handful (δραχμή), cf. Plu.Lys.17.)