The main difference between a coin and a token lies in their underlying blockchain and functionality. A coin is a digital currency that operates on its native blockchain. Examples include Bitcoin (BTC), Ethereum (ETH), and Litecoin (LTC). These coins are typically used as a medium of exchange, store of value, or to power transactions and smart contracts on their respective blockchains.

In contrast, a token is a digital asset that is built on top of an existing blockchain. For example, most tokens are created on Ethereum using its ERC-20 or ERC-721 standards. Tokens do not have their blockchain and rely on the network they are built upon for security and operation.

Coins are usually used to pay transaction fees or as digital money within their ecosystems. Tokens, however, can serve multiple purposes such as representing assets, granting access to services, or acting as governance tools in decentralised applications (dApps).

In summary, coins have their blockchains, while tokens are built on existing ones. Both play vital roles in the crypto economy, but understanding their differences is important for making informed investment or development decisions.