A
- About Uncirculated (AU)
- A coin with only the slightest trace of wear on its highest points, graded AU-50 to AU-58.
- Alloy
- A mixture of metals. Most US coins are alloys, such as 90% silver and 10% copper.
B
- Bag marks
- Small nicks on uncirculated coins caused by contact with other coins in mint bags.
- Blank / planchet
- The plain metal disc that becomes a coin when struck between two dies.
- Bullion
- Precious metal valued by weight and purity rather than collector demand.
- Business strike
- A coin made for everyday circulation, as opposed to a proof.
C
- Cameo
- Contrast between frosted design elements and mirror-like fields on a proof coin.
- Clad
- A coin made of layers: a pure copper core sandwiched between copper-nickel outer layers. Used for dimes and quarters since 1965 and for half dollars since 1971.
- Cleaned
- A coin whose original surface has been altered by polishing or chemicals. Cleaning lowers value.
D
- Denomination
- The face value of a coin, such as one cent or a quarter dollar.
- Denticles
- The small tooth-like beads around the rim on many older coin designs.
- Die
- The engraved steel cylinder that stamps a design onto a planchet.
- Die variety
- A difference between dies of the same coin, such as a doubled die or repunched mint mark.
- Doubled die
- A die that received two slightly offset impressions during manufacture, so every coin it strikes shows doubled design elements.
E
- Edge
- The outer surface around the coin, which may be plain, reeded (ridged) or lettered.
- Error coin
- A coin with a mistake made during striking, such as an off-center strike or the wrong planchet.
- Eye appeal
- The overall attractiveness of a coin, which affects price within a grade.
F
- Face value
- The legal monetary value stamped on a coin.
- Field
- The flat background area of a coin not occupied by the design.
- Full Bands (FB)
- Designation for Roosevelt and Mercury dimes with fully separated bands on the torch or fasces.
- Full Steps (FS)
- Designation for Jefferson nickels showing five or six complete steps on Monticello.
J
- Junk silver
- Common-date 90% or 40% silver coins traded for their metal value.
K
- Key date
- The scarcest and most valuable date in a series, often because of a low mintage.
L
- Large cent
- The original US cent of 1793 to 1857, about the size of a modern half dollar.
- Legend
- The main lettering on a coin, such as UNITED STATES OF AMERICA.
- Luster
- The cartwheel-like shine on an uncirculated coin caused by metal flow during striking.
M
- Melt value
- The value of a coin's metal content at the current market price of that metal.
- Mint mark
- A small letter showing which mint struck the coin, such as D for Denver or S for San Francisco.
- Mint State (MS)
- An uncirculated coin with no wear, graded MS-60 to MS-70.
- Mintage
- The number of coins of a particular date and mint that were struck.
- Motto
- An inscription such as IN GOD WE TRUST or E PLURIBUS UNUM.
N
- Numismatics
- The study and collecting of coins, tokens and paper money.
O
- Obverse
- The front or "heads" side of a coin, usually bearing the portrait and date.
- Overdate
- A coin struck from a die on which one date was punched over another, such as 1918/7.
P
- Pattern
- A trial coin struck to test a proposed design or metal, not issued for circulation.
- PCGS / NGC
- The two largest third-party coin grading services, which authenticate and encapsulate coins.
- Proof
- A coin struck for collectors with specially prepared dies and planchets, usually with mirror-like fields.
- Prooflike (PL)
- A business-strike coin with reflective, mirror-like fields, especially Morgan dollars.
R
- Reeded edge
- An edge with fine vertical ridges, found on dimes, quarters, halves and most dollar coins.
- Relief
- The raised parts of a coin's design.
- Repunched mint mark (RPM)
- A mint mark punched into the die more than once, leaving a doubled appearance.
- Restrike
- A coin struck later than its date, often from original dies, for collectors.
- Reverse
- The back or "tails" side of a coin.
S
- Semi-key
- A date scarcer than average but less valuable than the key dates of a series.
- Sheldon scale
- The 1 to 70 numerical grading scale used for US coins.
- Slab
- Slang for the sealed plastic holder a grading service puts a certified coin in.
- Special Mint Set (SMS)
- Collector sets issued 1965 to 1967 in place of proof sets.
- Strike
- How completely the design was impressed onto a coin; a "weak strike" shows soft details.
T
- Toning
- Natural color that develops on a coin's surface over time through oxidation.
- Troy ounce
- The unit used for precious metals: 31.103 grams, about 10% heavier than an ordinary ounce.
- Type coin
- One representative example of a design type, collected instead of every date.
V
- VDB
- The initials of Victor David Brenner, designer of the Lincoln cent, which appear on 1909 reverses and, from 1918, on Lincoln's shoulder.
W
- War nickel
- A Jefferson nickel struck from 1942 to 1945 in an alloy containing 35% silver.
- Wheat cent
- A Lincoln cent of 1909 to 1958 with two wheat ears on the reverse.
More terms for how coins are made
Hub: a steel punch carrying the design in relief, used to sink the design into working dies. Master die: the die made from the master hub, from which working hubs and then working dies are produced. Collar: the steel ring around the planchet during striking that forms the edge and keeps the coin round. Upset rim: the raised edge pressed onto a blank before striking, which helps the metal flow into the design.
Die marriage: a specific pairing of one obverse die with one reverse die. Collectors of early coins identify die marriages by numbers in standard references. Adjustment marks: file lines on early silver and gold coins made at the Mint to bring an overweight planchet down to legal weight.
Terms for condition and denomination
RD, RB and BN: color designations for copper coins meaning red, red-brown and brown. DMPL: deep mirror prooflike, a business strike with fields reflective enough to read print at a distance. Cud: a raised blob on a coin caused by a piece breaking off the edge of the die.
Eagle, half eagle, quarter eagle and double eagle: the names for the ten-dollar, five-dollar, two-and-a-half-dollar and twenty-dollar gold coins. Trime: the three-cent silver coin of 1851 to 1873.
Frequently asked questions
What is the difference between a hub and a die?
A hub carries the design raised, like a coin. It is pressed into a die, which carries the design sunk in reverse and strikes the coins.
What does RB mean on a copper coin?
RB means red-brown, a copper coin that keeps part of its original red color. RD is full red and BN is brown.