Wikipedia
In the study of numismatics, tokens are coin-like objects used instead of coins. The field of tokens is part of exonumia. Tokens are used in place of coins and either have a denomination shown or implied by size, color or shape. "Tokens" are often made of cheaper metals: copper, pewter, aluminium, brass and tin were commonly used, while bakelite, leather, porcelain, and other less durable materials are also known.
The key point of difference between a token and a coin is that a coin is issued by a governmental local or national authority and is freely exchangeable for goods or other coins, whereas a token has a much more limited use and is often (but not always) issued by a private company, group, association or individual.
In the case of "currency tokens" issued by a company but also recognized by the State there is a convergence between tokens and currency.