Coin Collecting Terms - Letter
O
[A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M]
[N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]
Obol - A small ancient Greek silver coins (worth 1/6 of a drachma).
Obsolete bank note - Note of an American bank of issue prior to 1865; a more accurate term than "broken" bank note, since many note-issuing banks converted into national banks or liquidated without failing.
Obverse - The front or face side of a coin, generally the side with the date and the principal design.
Oct - Synonym for octagonal – the Pan-Pac octagonal commemorative fifty-dollar coin.
Off center - An error caused by incorrectly centering the planchet during the striking process, which results in part of the design missing from the coin.
Offset - Printing method in which a metallic plate places an ink impression on an elastic blanket and is then transferred to the paper. Also, a term sometimes used to describe a blanket impression paper money error.
OPA token - A cardboard fiber token issued in the United States by the Office of Price Administration in 1944 during World War II. Both sides of the OPA token depicts a numeral 1 flanked by two small initials.
Open collar - A device used to position a planchet over the lower die. It was employed specifically for striking early US coins whose edges had already been stamped with reeding or lettering.
Orange-Peel - A) Term used to describe an odd roughness on the surface of a coin as it was struck resembling the skin of an orange. B) Used to describe the color on certain gold pieces.
Ore - A naturally occurring solid material from which metals are mined.
Original - Referring to any aspect of a coin that retains its original state. Original toning means natural, not retoned or cleaned. Original luster means undisturbed luster that hasn’t been enhanced through artificial methods.
Original roll - A roll of coins, all the same date, denomination, and mintmark, and usually of the same die variety, which seem to have been acquired by the same original owner, probably from the same original mint bag. Generally, all the coins in an original roll will have similar toning and luster.
Original toning - Referring to a coin that has never been cleaned or dipped. Original toning ranges from a very mild yellow to extremely dark blues, grays, browns, and finally black.
Over dipped - A coin whose luster has been dulled from too many baths in a dipping solution.
Over-mintmark - One mintmark on top of a different mintmark, such as a 'D' over an 'S' (denoted D/S)
Overdate - A date made by superimposing one more numbers on a previously dated die.
Overgrade - The practice of assigning a higher grade to a coin than it truly deserves.
Overgraded - Designated with a higher grade than merited.
Overstrike - An impression made with different dies on a previously struck coin.
Oxidation - The formation of oxides or tarnish on the surface of a coin from exposure to humidity, air pollutants, or other environmental elements.