https://nnp.wustl.edu/library/dictionary) defines a pattern as a coin which has not been approved for release, produced to evaluate a proposed coin design, or a term which includes a wide array of early strikes including die trials, hub trials, die adjustment strikes, experimental pieces and other trial pieces; anything that is different from the production run that is not a mint error. I would not call a die or hub trial a pattern, nor would I consider a die adjustment strike to be a pattern (though you could have a trial or adjustment strike of a pattern). I feel like major sources seem to define what a pattern is differently from each other and there is not a consensus on this definition. What do you all consider to be or not be a pattern? To me, a pattern is a version of a coin that is proposed for release. I see several types, and think there is generally a consensus that what I've listed here as types 1-3 are patterns. Not Produced - A type that was not approved and/or not produced Working Version - A type that was eventually approved, but with modifications made Final Version - A type that was approved as-is (Note: some countries mark patterns with words or letters denoting the coin as a pattern - it is assumed these markings are removed for the final version and they still fall into this type) Transitional - As type 3 above, but dated outside (usually a year earlier or later) of the business strike run (for example the 1856 flying eagle cent). Some transitional patterns eventually get released into circulation as they are identical to the business strikes except for the date, which can cause confusion in identifying them as a pattern. Off-metal - An approved type on a proposed planchet of alternate thickness or composition Fantasy - Patterns as above, except produced for the collector market, usually in large quantities. For example, Hungary is not on the euro, but since they became an E.U. member state they have produced fantasy pattern sets of proposed euro designs. Then you also have test strikes, die splashes, and die adjustment strikes, which to me are artifacts produced during the production of a coin but are not patterns in and of themselves. I include them here since they are included in the NNP definition: Test strike - A uniface die strike, typically on a softer and/or more inexpensive metal than the intended coin. I suppose you can have a bi-face test strike, but that becomes hard to distinguish from an off-metal pattern since you need to know if the intent was to produce an example of a proposed planchet change (an off-metal pattern), or if it was just produced to test the dies (a bi-face test strike). Die splash - A test strike as above, but struck without a collar, sometimes on a large and/or irregular planchet Adjustment Strike - A test strike made to verify the correct pressure and/or alignment in a coin press Here are some examples from my collection: Hungary 1922 5 Korona Adamo KE5 - Nickel Planchet Early Version - No Initials Under Shield NGC MS65 This pattern is an example of a type 1 (above) Not Produced. Due to a change in Hungary's coat of arms and post-WWI hyperinflation that led to an overhaul of all denominations, this coin was never produced. The 5 korona (silver) denomination itself was ultimately not produced for circulation after 1909. Hungary 1950BP Copper-Nickel 2 Forint KM-548p NGC MS67 This pattern is an example of the second type - Working Version. The size of the inner star on the obverse was adjusted for the business strike. The PV mark (denoting a pattern) was also removed. Hungary 1992BP 5 Forint Pattern Proof Nickel-Brass This pattern is an example of the third type - Final Version. This coin was approved for production as-is, and only the "Probaveret" legend (denoting a pattern) was removed. Hungary 1916KB 2 Fillér Huszar-2225 Iron Planchet NGC AU58 This pattern is the closest I have to an example of the fourth type - Transitional, though the planchet composition, diameter, and thickness were also adjusted. Aside from the planchet changes above, the design is based on the bronze 2 fillér KM-481, which was struck from 1892-1915. This coin, dated 1916 falls one year after that range, making it a type of transitional pattern. Austria 1916 Corona KM-PN85 Aluminum Planchet NGC MS62 This is an example of the fifth type, an Off-Metal pattern. In this case, it is identical to a silver 1916 corona except for the prototype aluminum planchet and the use of a reeded collar. Note for this coin, Krause has denoted it a pattern. It is definitively known that the purpose of this coin was for a proposed planchet composition change. Clashed 1916 working dies were used to strike this off-metal pattern, with the most likely intent that the type begin production in aluminum in 1917, however, it was ultimately not produced due to the death of Emperor Franz Joseph on November 21st, 1916. Note that if the type change had occurred in 1917, it would have made this a transitional pattern instead of an off-metal pattern. Hungary 1896 Dukát (Karoly Robert Type) Hungarian Millennium X-9 Obverse Test Strike in Lead This is an example of a traditional uniface Test Strike. A lead planchet was used to test the obverse die for this gold type, and the type information was scrawled on the back to record it (sorry I don't have a reverse pic handy). Hungary 1883KB Krajczár KM-TS29 Nickel Planchet NGC MS65 This coin is identical to the copper business strike 1883 krajczár, except it is struck on a nickel planchet. Note that in this case, Krause denoted it a test strike and not a pattern. To me, for this to be a bi-face test strike, it would have needed to be produced purely for the purpose of testing the dies. That seems unlikely, as supporting evidence points to several years around this period where the Austro-Hungarian mint were experimenting with proposed alternate planchet compositions for minor coinage (which to me would be patterns). However, it is unusual that this coin was produced in the middle of the run of the copper business strike type. While I consider this to be a pattern, this may in fact be an example of a bi-face test strike. Austria 1898 Signvm Memoriae Franz Joseph I Jubilee Obverse Die Splash This is an example of a traditional uniface Die Splash. The obverse die of this medal was struck on a bronze planchet without a collar in order to test the die. Hungary 1870GYF 10 Krajczár KM-451 Obverse Die Splash Struck in Tin From GYF Mint Archive Book This is a non-traditional example of a uniface Die Splash. This type was struck or pressed in lead-tin without a collar (it is wafer thin). In this case the purpose was to be glued into the mint archive book to record the type at the GYF mint. (The date is known as I also have the uniface reverse from this pairing, and the provenance).