"Doug forwarded your e-mail because he knows I am working on a "Canadian Dictionary of Numismatics" and that the question from Bob Knepper would definitely interest me. Here is the light I can shed on the subject:

MEDAL: CoinNews (UK) define the term in their 2000 Yearbook as "A piece of metal bearing devices or given as an award. Military medals date generally from the 16th and 17th centuries, but were not generally awarded to all ranks until the 19th century. Commemorative medals can trace their origin back to Roman times, but in their present form they date from the Italian Renaissance when there was a fashion for large-diameter cast portrait medals." They further state that a "medalet" is a small medal of 25mm or less and a "medallion" is a large medal of 50mm or more. I must add some caveats in that "Military medals" are commonly referred to in North America as "decorations" to avoid confusion. Furthermore, even though "medal" is the more generic term, the tendancy in North America is to use "medallion" as the generic with "medal" being the larger size one.

JETON: CoinNews "Alternative term for "counter", and used originally on the chequerboard employed by medieval accountants. Nuremberg was the most important centre for the production of medieval jetons, often issued in lengthy portrait series. Carlton in his "International Encyclopaedic Dictionary of Numismatics" simply states that it is the French translation of "token". Carlton is quite right to say so, particularly in North America. However, Gallléazzi in his "Lexique numismatique" clarifies that for the French there are three types of jetons: jetons de compte (usually refered to as jetons or counters in English), jetons de circonstance ou à thème (would more appropriately be translated as a medal) and jetons-valeurs (appropriately translated tokens).

TOKEN: CoinNews "Any piece of money whose nominal value is greater than its intrinsic value is, strictly speaking, a token or promise. Thus most of the coins issued since 1964 can be regarded in this light, but numismatist reserve the term for a piece of limited validity and circulation, produced by tradesmen, chambers of commerce and other organisations during times of a shortage of government coinage. (...) Tokens with a nominal value may be produced for security reasons to lessen the possibility of theft from milk bottles, vending machines, telephones, parking meters...

My simplified and simplistic approach to it is as follows: I only use "jeton" in English to describe medieval counters; any piece with a denomination or a "good for" value on it is a "token", and everything else that is not a coin is a "medal"!

So, I hope this will help Mr. Knepper. I don't know what he collects but he should definitely consider Municipal Trade Tokens for his thematic collection."

"In the microtrivia category: You may have gotten other responses, but will comment since I just happened to be reading a Spanish paper about a countermark on a jeton. The (Spanish) author distinguishes between the two terms as in your comment, and uses "contramarca" for countermark as you defined, but uses "resello" for your definition of "counterstamp." The paper I'm referring to was published by Juan Jose Moreno y Casanova, "Contramarca privada sobre un jeton frances," Gaceta numismatica 126, 49-56 (1997). (I'm not touching the "jeton" part of the definitions!}"

"I will take a stab at the differences between medals, tokens and jetons. Medals are items which commemorate things, events and people. Tokens are items used for exchange or goods. Jetons are counting tokens used originally to calculate mathematics and later, with the advent of modern math spreading throughout Europe by the early 1600s, found other purposes as presentation pieces, propaganda devices and small medals."

"A jeton is a little medal. A token can be used for some kind of payment. An advertising piece is a jeton and a communion token is still a token, even the admission is free."