Native Asset
The built-in asset of a blockchain itself, used to pay transaction fees and, on proof-of-stake networks, to secure the network.
A native asset is issued by a blockchain's own consensus rules rather than by a contract running on top of it: the node software itself tracks balances and mints new units according to the protocol. This is the technical difference behind the casual word coin. Bitcoin on the Bitcoin network, ether on Ethereum, and SOL on Solana are native assets; a token on any of those chains needs the native asset to pay for its own transfers. Native assets usually carry protocol jobs that tokens cannot have, such as paying gas, being bonded as validator stake, and receiving block rewards.
In practice
Ether is Ethereum's native asset: it pays gas for every transaction on the network, including transfers of tokens that are not ether.
The common misunderstanding
Coin and token are used interchangeably in casual writing, but a coin is minted by a chain's own consensus rules while a token is minted by a contract running on top of a chain.