Crypto glossary
Receipt token (aToken, cToken)
A receipt token is a token a DeFi protocol issues when you deposit assets, proving your claim on them and often accruing interest, fees or staking rewards.
When you supply USDC to Aave you receive aUSDC; on Compound v2 you received cUSDC; a liquid staking protocol gives stETH for ETH; a vault mints shares for each deposit. These tokens are receipts: burning them returns the underlying asset plus whatever it earned. Some grow in number in your wallet, while others keep a fixed balance and rise in exchange rate against the underlying.
Because the receipt is itself a token, it can be transferred, traded or used elsewhere, which is the basis of DeFi composability. A user can deposit ETH, receive a staking receipt, post it as collateral, borrow stablecoins and deposit those to receive yet another receipt. Standards such as ERC-4626 make vault receipts easier to integrate.
A receipt is only as good as the protocol that issued it: if the underlying contract is hacked or becomes insolvent, the token can lose value or become unredeemable. Wallets and tax tools may misread rebasing balances, and sending a receipt token to an exchange that does not support it can make it hard to recover.
Example
After depositing 1,000 USDC in a lending protocol, a user holds 1,000 aUSDC; a year later her balance shows 1,042 aUSDC, which she can redeem for 1,042 USDC.