If an object is struck by a government and given a monetary value by that government, it can be called a "coin", even if it isn't actually intended to circulate as money.
If a coin-like object is struck for some kind of monetary use but not by a government, then it's a "token", not a coin.
If a coin-like object has no monetary function or nominal face value, then it's a "medal", whether it was issued by a government or not.
I've heard several technical differences between "medal" and "medallion", but in practice, those two words are interchangeable. One such distinction is that "medals" are smaller, while "medallions" are larger. Another is the "method of manufacture" distinction biokemist mentions.
Personally, if I make any distinction at all, I tend to use "medal" for something that was given to somebody that did something to deserve it (like a war medal, or an Olympic medal) while I use "medallion" for something that was sold as a souvenir or fundraiser, given away as a PR stunt or otherwise available to anyone that wanted one. This does seem to follow the conventional "man in the street" understanding of the terms.
If a coin-like object is struck for some kind of monetary use but not by a government, then it's a "token", not a coin.
If a coin-like object has no monetary function or nominal face value, then it's a "medal", whether it was issued by a government or not.
I've heard several technical differences between "medal" and "medallion", but in practice, those two words are interchangeable. One such distinction is that "medals" are smaller, while "medallions" are larger. Another is the "method of manufacture" distinction biokemist mentions.
Personally, if I make any distinction at all, I tend to use "medal" for something that was given to somebody that did something to deserve it (like a war medal, or an Olympic medal) while I use "medallion" for something that was sold as a souvenir or fundraiser, given away as a PR stunt or otherwise available to anyone that wanted one. This does seem to follow the conventional "man in the street" understanding of the terms.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis