First things first, the terms ‘coin’ and ‘token’ are often used alike. The line between coins and tokens is not clear and sharp. Both are used to transfer value, as a means of payment, in a similar way to that both USD and shares are used to reward people for work.
A coin is a means of payment, a money equivalent, something that defines value and serves as a value transfer. Coins tend to take the form of native Blockchain ‘tokens’ like Bitcoin (BTC) or Ethereum (ETH).