Token is a digital unit of a certain value. They can be the equivalent of securities or a payment unit. It is also possible to exchange token on the stock exchange for another cryptocurrency or FIAT money. A benefit program for token holders is a common practice - receiving part of the company's profits, material rewards or discounts on trading fees.
Terms cryptocurrency, altcoin and token are often used as synonyms - but in reality each one means something different. Tokens are a subset of cryptocurrencies - they cannot be created by themselves. Cryptocurrency differs from a token by having its own blockchain, which makes it easier to create decentralized applications. In most cases, the blockchain of a given cryptocurrency allows you to create a new token.
Ethereum platform supports the creation of additional cryptocurrency tokens - examples such as Tron and EOS.