A token standard is a set of rules – defined by a smart contract – that enable the creation of an asset on a blockchain.
Some of the most popular token standards include ERC-721 on Ethereum, SPL on Solana, and BRC-20 on Bitcoin. These allow NFTs (or their equivalent) to be minted on these blockchains.
Token standards can also allow crypto tokens to be created on a blockchain. ERC-20 is the most popular crypto token standard on Ethereum, and has been used to create the likes of USDT, ApeCoin (APE), and ETH itself.