You left out one option in your poll. "When said disk has been smashed beyond all recognition." Chris
I respect everyone's opinion - especially when I'm the only one that voted a coin should only be round and non-concave (as of this post). However I draw the line (terminology-wise) when the object is no longer round or cannot be laid flat on an even surface. Governments may assign monetary value to them but I will refer to them as "metal objects of value", not coins.
I have a washer and a dryer. I have cookware. I have many other things made of metal. They are metal objects of value. Ask a coin dealer if he has any "metal objects of value" and let us know his response.
Frankly, it varies. Like @cpm9ball said, when it is unrecognizable and its denomination can not be obtained it becomes just a piece of metal. The shape of said coin is irrelevant, in my opinion. As long as it was produced for the intention of being used as a coin and is recognizable, it is a coin.
Yea I wouldn't expect a dealer to know what I am talking about if I simply asked him/her to show me "metal objects of value". To be fair I would probably never ask to see such items since I don't buy or sell them. However if I were to ever ask I would say "let me see those so-called coins". I really would say it that way too. The line has to be drawn somewhere and just cause others aren't willing to doesn't mean I won't. If we don't then the next thing you know they'll start making animal-shaped objects and calling them "coins". Look at Palau and their skull "coins". Most ridiculous thing ever! I would like to make one clarification to my previous assertions... if a coin was made round and even sided, as intended, but was damaged and no longer round or even, I would make an exception and call it a coin. But only in that instance!
All money/coins produced by a government have the value assigned by the goverment involved. Now, for the NCLT and proof coins I can see calling them collectibles as they are not intended to be used as money. For things that were 'used as money' to facilitate trade (like rice, tea bricks, chocolate, yap stones) I consider those trade or barter media, but not coins as they were not issued under a governments auspices. Coins are produced under a governmental authority to represent money/trade/value regardless of shape, or even material these days. Used to have a value based on precious metal...but that is a whole different conversation. If some governments choose to make their coins not-round is up to them. Just MHO of course.
I feel like a coin is a coin if A) it is or has been produced and recognized by some sort of government to have monetary value, with the shape size and metal playing no effect.
Even the first coins were not round + could not be laid flat here are a few ancients that can't be laid completely flat.. 400-300 BC + Most byzantine coins were convex for a few hundred years Manuel I Struck circa 1167-1183.
In my mind I'm separating the terms money and coins. Money to me means value. Coins meaning the physical shape. I think that's why there is a difference of opinion among myself and the majority of others here. I think most here consider anything that is money to be a coin. Btw, I don't see any of the poll options as right or wrong. Just how someone interprets the term "coin".
How do you see Massachusetts silver? They were often warped and wouldn't lay flat even right after they were made. (rocker press, tends to warp thin coins into a shallow S shape.)
Olympic medals. Usually smoothly round and flat. Are they coin? No. Big majority of people in the world, perhaps, all of them consider that coin is money, one of various forms (metal, paper, card, etc) of money.But, coin is "root" form of money. It is so not because of its material, metal, history, etc. but, because money math root is in the coin. First step of math of money is in the coin. So, without mathematics, no any round or whatever shaped physical object can be considered as money. Like math, money is an imaginary concept, an imaginary tool. Cash money, a physical object makes this imaginary concept of math a concrete item. And, root form of physical cash money is coin... Also, very first labor effort in physical money is in the coin, even before the math in the coins... So, to me, in this order: 1. labor (in every stage including beginning) 2. physics 3. add basic mathematics 4. result=coin... 5. add advance phys math art etc = paper money and other forms of money.
I think there are a billion or so people who would disagree with you about the 'round' requirement . I read a nice description of what a coin is on wiki and have adapted it with a few additions Basically being small, flat (though I would argue the Byzantine pocket change would be the exception), usually round (though obviously not always), pieces of metal (or plastic, or porcelain, or clay--I added that one as the so-called porcelain coins of Japan aren't exactly porcelain). They are legal tender (so that takes out tokens even though they can be used like a coin) used as a medium of exchange. Standardized in weight (plus diameter and content I would add) with a specified value. Produced in large (define large) quantities at a mint (I would say government or contracted facility), and produced in order to facilitate trade. So, not bullion (a store of value based on metal content and can be used as trade). Proofs, well I count them as coins, just pretty versions of the 'facilitating trade versions'. As for trials/provas/essais. Hmm. Special circumstances because I like a lot of them. But I give a hearty NO to NCLT as coins as they really aren't meant to circulate by definition. Love some of 'em, but no. Merchant tokens fail on the government and legal tender aspect, even though they do 'facilitate trade'. Now, all those are collectible and may or may not have a face value or intrinsic value based on content, BUT are they truly coins? All interesting to consider, however I do take exception to the whole round part. (Unless I misread the entire of the premise and you were really talking about damage to a previously round coin...as in how much damage can it take and still be a coin. Then my answer is 'it's a coin as long as the vending machine will still take it').
They don't necessarily have to be legal tender. Were half cents and large cents coins? Large cents weren't legal tender until 1864, half cents weren't legal tender until 1965. And I would make that last part "issued with the intent they would be used as a medium of exchange." The Somalia pieces are legal tender, but weren't actually intended to be used as a median of exchange. They COULD be used though.
Why did Somalia make coins with the United Kingdom and United State's flags on them? ...seems like an odd concept.