Originally a weight of ancient Greece, and later a silver coin, the one sixth of the Brachm (q.v.). The etymology of the name is uncertain, but the generally accepted theory is that it is derived from ??????, i.e., a spit, or skewer, the appellation given to the earliest iron bar money which was made in this form. The normal weight of the Obol was 0.73 grammes, or 11.25 grains.
The multiples of the Obol consisted of
Pentobolon = 5 Oboli
Tetrobolon = 4 Oboli
Triobolon = 3 Oboli
Diobolon = 2 Oboli
Trihemiobolion = 1 1/2 Oboli
The divisions of the Obol were the following:
Tritemorion = 3/4 of the Obol
Hemiobolion = 1/2 of the Obol
Trihemitetartemorion = 3/8 of the Obol
Tetartemorion = 1/4 of the Obol
Hemitetartemorion = 1/8 of the Obol
The last named coin was the same as the Chalcus (q.v.). By Roman times the Obol had degenerated into a bronze coin. At Athens the Obol of gold was another name for the gold Hemihecte (q.v.).
The Obol was the coin which it is said was put in the mouth of deceased persons to pay to Charon for their passage over the Styx. See Naulum.
Synonyms: Obolus, Obolos
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)