This is an ongoing work (one of those never-ending projects) consisting of a compilation of all known names used for coins from the ancient times to the present. Where possible, a description of coins of that name is given, as well as the most likely origin of the name, including translations. In many cases, links are made to pages which will show various examples of that denomination. Obviously, the images not all-inclusive but hopefully will give the user an idea of what some of the coin denominations looked like and how coins of the same name differ from country to country and through time.

Oban - [Japan]

Obol - A small Greek silver coin, valued at one-sixth of a drachm.

Its name is derived from obelos (a spit) just as drachm comes from drax (a handful [of spits]).  This would indicate that both coins were the next step up from a monetary system that used iron cooking spits as a medium of exchange.  Although it is not known for certain when the obol was introduced, it has been placed somewhere in the sixth century B.C.

The term was also applied to the half denar.  The first German obols were struck by Charlemagne in the 8th century.  The denomination is not often encountered, and almost disappeared entirely after the denar itself became so debased as not to warrant minting halves.  Subsequent German half pfennig coins are occasionally referred to as obulii or obols.

{From Greek obelos a cooking spit, formerly used as currency in a barter economy.}

[Ancient Greece, Holy Roman Empire]

Obole - A small French coin originally struck in silver, but later of billion, that was in use from the 10th through the 15th century.  It was also called a maille.  It has the value of 2 denier.

[France]

Oboli - Plural of the ancient Greek obolus.

Obolo - Variant of obol in Italy.

{From Italian obolo mite, contribution, alms.}

Obolus - A silver (in later times bronze) coin of ancient Greece of the value of one-sixth drachm.  Later, a term applied to the French obole, and to other coins, mostly of small value, formerly current in Europe.  It was also used allusively for any small coin.  See obol.

[Ancient Greece, France]

Obulii - Plural of the German obol.

Ochavo - [Spain]

Ochr-el-Guerche

Octavo - [Mexico, Philippines]

Octuple - [Avignon]

Omani Riyals

Onca - [Mozambique]

Oncia - A gold coin of Charles III (1734-1759) equal to 6 ducats.  Also, a silver coin of Charles VI of Austria equal to 30 tari.

Ongaro - Called in Italy the Ducat of gold struck by the kings of Hungary.  A gold coin of Livorno struck in the late 17th Century.

[Italian States-Livorno]

Onluk -

{From Turkish onluk of ten parts; worth ten [piastres]; ten piastre or para piece.}

[Turkey]

Onza - [Bolivia, Chile, Costa Rica, Mexico]

Or - [Sweden]

Øre - A bronze coin of Norway, valued at the 100th part of a krone.

A zinc or bronze coin of Denmark, with the a value of 100th a krone.

{1600-1610: Ultimately from Latin aureus a gold coin.}

[Denmark, Norway]

Öre - A bronze coin of Sweden, the 100th part of a krona.

A fractional currency of the Faeroe Islands, the 100th part of a krona.

{1600-1610: Ultimately from Latin aureus a gold coin.}

[Sweden]

Ore, K.M. - [Sweden]

Ore, S.M. - [Sweden]

Ort -

{From German ort quarter; quarter piece (of thaler, guilder etc)}

[Courland, German States, Poland]

Orte - [Lithuania, Poland]

Ortsthaler - Quarter thaler.  This denomination was particularly important from 1500 to 1667, during which time it generally weighed about 6.5 grams and was about 29 millimeters in diameter.  The 1/8 thaler was called the "half ort."

[German States]

Ortug - The largest Swedish denomination.  Equal to 4 penningar, it was first struck under King Albrekt of Mecklenburg (1364-1389).  It was minted primarily at Stockholm and Kalmar.  The obverse had the king's head and the reverse a cross, but under Erik of Pomerania, the shield of Sweden with 3 crowns was used.

[Sweden]

Othmany -

Ouguiya - Plural ouguiya, ouguiyas.  A cupronickel-aluminum coin and monetary unit of Mauritania, equal to five khoums.

{1970-1975: From French from Arabic dialect ugiya akin to Arabic uqiyah ounce, from Greek ounkia from Latin uncia.}

[Mauritania]