Controlling the authorization needed to move your own blockchain assets.
Self-custody puts signing control in your hands rather than an exchange's. Recovery becomes part of your setup: the app, device, backups and account rules need to work together. Some wallets use multiple keys or guardians, so self-custody does not always mean relying on one seed phrase.
IN THE WILD
You review a transfer and sign it with your own hardware wallet; there is no exchange withdrawal request to approve.
A component or participant that orders transactions for execution in a scaling system.
The sequencer decides how incoming transactions are arranged before they become a batch. Its quick response can make an app feel responsive, but is different from settlement on the base chain. If sequencing is centralized, availability and transaction inclusion can depend on that operator until other mechanisms take effect.
IN THE WILD
"The rollup accepted my transaction quickly. Its sequencer response came before the batch settled on Ethereum."
A cryptographic hash algorithm in the SHA-2 family that produces a 256-bit digest.
The 256 describes the output length, not the input's size. Bitcoin uses SHA-256 in several constructions, including applying it twice to a block header for proof of work. The result is a digest for checking data and work rather than an encrypted version of the header.
A separate blockchain connected to another chain while using its own consensus security.
A sidechain can make asset representations or messages available in another environment through a bridge. Its validators and consensus rules still determine its own chain's security. Being connected to Ethereum does not automatically give it Ethereum's security, so bridge assumptions and sidechain consensus are both part of the picture.
IN THE WILD
"I bridged out of Ethereum. This sidechain's own consensus now secures the chain where the representation lives."
A protocol penalty that removes stake for specified, provable validator misconduct.
Slashing is reserved for particular rule violations, such as signing conflicting messages where the protocol forbids it. It's different from every missed duty or ordinary downtime penalty. One practical hazard is running duplicate validator instances with the same signing keys: they can produce conflicting signatures even without someone intending to cheat.
IN THE WILD
Before moving a validator to another server, you shut down the old instance so both machines won’t sign conflicting messages with the same keys.
The difference between an expected execution result and the result actually obtained.
A quote can change before the transaction executes because prices move or available liquidity changes. In AMM interfaces, slippage is commonly separated from price impact already included in the quote. The distinction helps explain whether the difference arose from the planned trade itself or from conditions changing after the quote.
IN THE WILD
"The quote was 100 tokens, but the swap returned 98 after the pool's conditions changed."
The maximum unfavorable difference from a quoted trade that a user agrees to accept.
Slippage tolerance sets an execution limit, such as the minimum tokens you'll receive. Raising it makes room for a worse outcome; it doesn't improve liquidity or remove price impact. If the limit can't be met, an included transaction can revert and still cost gas. Treat the setting as permission, rather than a fee you automatically pay.
IN THE WILD
You leave a 1% tolerance on a swap, and it reverts after conditions move beyond that limit instead of completing at the worse price.
A scheduled time interval in which a proof-of-stake network may produce a block.
On Ethereum, each slot has a selected proposer, but that doesn't guarantee a block will appear. If the proposer misses its turn, the slot can remain empty and the schedule carries on. Slots organize when duties happen; they're grouped into epochs that provide another layer of consensus timing.
IN THE WILD
An explorer shows an empty Ethereum slot between two blocks because the selected proposer didn’t produce a block for that turn.
An account with programmable rules for authorizing and carrying out actions.
A smart account can define how actions are approved rather than relying only on a single conventional signature. Depending on its design, it might require several signers, offer recovery or batch calls. Those rules are part of its security model: check who can recover the account and what permissions they gain.
IN THE WILD
Your account requires two signers for a large transfer, while allowing a limited session permission for routine actions in a game.
A program on a blockchain that executes defined rules when it is invoked.
A smart contract lets participants interact through code that the network executes and checks. It can manage swaps, loans, tokens or many other actions, but the name doesn't promise clever code, security or a legal agreement. Read what it does, who can change it and which outside inputs it trusts.
IN THE WILD
You approve a lending transaction, and the contract checks its rules before recording your deposit and issuing the corresponding position.
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.