What is a Coin
Each blockchain has its own coin. This may include coins such as Bitcoin (BTC), the first crypto asset that was created. There are other coins which have their own blockchains such as Ethereum (ETH) and Binance (BNB).
What is an Alt Coin
An Alt or Alternative coin is in essence any coin other than Bitcoin (BTC). People refer to Bitcoin (BTC) as the first coin and the store of value and as such any other coin is considered an alternative to Bitcoin (BTC).
What is a Token
A token is a cryptocurrency that sits on top of a blockchain such as ETH or BNB. Typically tokens are used for security or utility related purposes which may include things such as NFTs or even Decentralized Finance (Defi).