Glossary

Plain-language definitions of the terms you'll see in Superbridge and in this help center.

Approval

Permission you give a contract to move a specific token from your wallet. You usually approve once, before a token's first transfer. Approvals

Attestation

Circle's confirmation that USDC was burned on one chain, so the same amount can be created on another. Activity shows Waiting for attestation during this step. Send USDC with CCTP

Bridged token

A copy of a token created by a bridge, rather than issued by the token's creator. Bridged versions often have a suffix, such as USDC.e.

Challenge period

A waiting period during a native bridge withdrawal. It gives time for an invalid withdrawal to be disputed before tokens are released. On chains that settle on Ethereum it's usually about 7 days. Withdraw with a native bridge

Custom gas token

A token other than ETH that a chain uses to pay for gas. Chains with a custom gas token

Dispute game

The system OP Stack chains use to check claims about their state. A withdrawal is proved against a dispute game, and can only be finalized once the game is resolved in its favour. When a withdrawal resets

Finalize

The last transaction of a native bridge withdrawal or manual transfer. It releases your tokens on the destination chain.

Gas

The fee you pay a blockchain to process a transaction. It's paid in the chain's gas token, usually ETH. Network fees

L1

Layer 1. A base blockchain that secures itself, such as Ethereum.

L2

Layer 2. A chain that settles on an L1, usually a rollup. Base, Optimism and Arbitrum One are L2s that settle on Ethereum.

L3

Layer 3. A chain that settles on an L2 instead of an L1. For example, a chain that settles on Base.

Native bridge

A rollup's own bridge, built into the chain and its settlement chain. Deposits are quick. Withdrawals are slower, because they wait for the rollup's security checks. How native bridges work

Price impact

How much your trade itself moves the price, because of the liquidity available. Large swaps in small markets have higher price impact. Swaps

Prove

The second transaction of an OP Stack withdrawal. It shows the settlement chain that your withdrawal happened, and starts the challenge period. Withdraw with a native bridge

Relayer

A service that submits a transaction for you on another chain, usually to deliver your tokens. Relayers charge a relaying fee. Fees

Rollup

A chain that runs transactions itself, then posts the results to another chain for security. Most L2s are rollups.

Settlement chain

The chain a rollup posts its results to, and relies on for security. It's usually Ethereum, but can be another L2. Native bridge withdrawals go back to the settlement chain. How native bridges work

Slippage

The most the price can move against you between quoting and completing a swap. If it moves further, the swap is cancelled. Swaps

Smart contract wallet

A wallet run by a contract rather than a single private key, such as a Safe or a Coinbase Smart Wallet. They may not exist at the same address on every chain. Send to another address

Superchain

A group of OP Stack chains, including OP Mainnet and Base, that share standards and upgrades.