A signing setup disconnected from networks that exchanges transaction data through a separate transfer method.
An air-gapped signer needs no direct network link to authorize a transaction. Another device prepares the request, and a QR code or removable storage moves the data across. The signed result returns for broadcasting. Those transfer methods still require trustworthy software and checks of the requested transaction.
IN THE WILD
The offline signer receives your unsigned PSBT through removable storage and returns a signed file for the connected device to broadcast.
The amount an ERC-20token owner has authorized a particular spender to transfer.
The token contract records an allowance for an owner-spender pair. The spender can use transferFrom within that allowance and the contract's rules without a fresh owner signature each time. It is a spending limit, not an app deposit or permission over every token in the wallet.
IN THE WILD
"There are 500 tokens in my wallet, but this spender's allowance is 50. It doesn't get the other 450 through that permission."
An onchain action that removes or reduces an existing token-spending permission.
For an ERC-20token, revoking commonly means setting a spender's allowance to zero. Once effective, this closes that route for future spending. It does not undo completed transfers, and is a different problem from replacing account control after a private key has been exposed.
IN THE WILD
"I stopped using that DEX. Setting its tokenallowance to zero removes that spending permission once the change takes effect."
Annual percentage rate: in DeFi yield displays, an annualized rate usually quoted without compounding periodic returns.
APR puts a rate on an annual scale without assuming that each payout is reinvested. A DeFi display can change as rates or incentive rewards change, so the number may describe current conditions rather than a fixed year-long result. Regulated borrowing disclosures can use more specific definitions of APR.
IN THE WILD
My example spreadsheet starts with 1,000 units at a constant simple 5% APR: 50 units over a year before costs.
Annual percentage yield: an annualized measure that includes the stated effect of compounding.
APY accounts for earning on earlier earnings under the calculation's assumptions. A DeFi display may assume reinvestment and particular reward rates, so comparing two numbers means checking how each was calculated. If rates change or rewards are not reinvested as assumed, the actual result can differ from the displayed projection.
IN THE WILD
"Why is the APY higher than the APR?" This display assumes each periodic earning is reinvested and earns more too.
Attempting to capture price differences between related assets, markets or trading routes.
An asset can trade at different prices in two pools at the same moment. Arbitrage tries to use that gap, often helping bring prices closer together. The headline difference is not the final result: fees, execution timing, inventory and settlement problems can consume the apparent profit.
IN THE WILD
"Pool A is cheaper than pool B." The trader checks whether buying in A and selling in B leaves anything after the route's costs.
A price at which a participant or trading system is prepared to sell an asset.
The best displayed ask is the lowest visible selling price in an order book. Its quantity limits how much can be bought at that level. A larger purchase may reach higher asks, so the lowest displayed price does not necessarily apply to the whole planned trade.
IN THE WILD
"One unit is available at the 101 ask. Buying more means checking the next sell levels too."
An operation whose included state changes succeed together or are rolled back together under the execution rules.
Atomicity lets a contract combine dependent steps without leaving half the intended state change completed. If a required step fails, the operation can revert those changes. This is useful for workflows such as flash loans, although rolling back the changes does not necessarily refund execution fees.
IN THE WILD
"The flash-loan workflow couldn't repay, so it reverted. It didn't get to keep the loan and half a completed swap."
On Ethereum, an attestation includes a view of the chain head and checkpoint votes used by consensus. It helps the network choose between valid branches and move toward finality. Validators need to vote correctly and on time, so these messages are an operational duty rather than a casual approval button.
IN THE WILD
Your validator sends an attestation for the chain it sees, and that vote contributes to fork choice and checkpoint finalization.
A trading mechanism that uses an algorithm and available liquidity to quote or determine exchange prices.
An AMM doesn't need to find another person placing the exact opposite order at that moment. Its rules use available liquidity to work out a trade. Different designs use different curves or price ranges, and a large swap can move the effective price significantly. The quoted price depends on the pool you're using.
IN THE WILD
You increase a swap from a small amount to a much larger one, and the AMM quote worsens because that trade uses more of the pool’s liquidity.
The daily pick rotates automatically. Our initial collection was published on October 9, 2026. New words join on their publication date. Every concept includes a reference.