The result of interpreting all programs on the ledger at a given [tick height](terminology.md#tick-height). It includes at least the set of all [accounts](terminology.md#account) holding nonzero [native tokens](terminology.md#native-tokens).
A contiguous set of [entries](terminology.md#entry) on the ledger covered by a [vote](terminology.md#ledger-vote). A [leader](terminology.md#leader) produces at most one block per [slot](terminology.md#slot).
A preimage resistant [hash](terminology.md#hash) of the [ledger](terminology.md#ledger) at a given [block height](terminology.md#block-height). Taken from the last [entry id](terminology.md#entry-id) in the slot
The number of [blocks](terminology.md#block) beneath the current block. The first block after the [genesis block](terminology.md#genesis-block) has height one.
The wallclock duration between a [leader](terminology.md#leader) creating a [tick entry](terminology.md#tick) and creating a [confirmed block](terminology.md#confirmed-block).
## confirmed block
A [block](terminology.md#block) that has received a [supermajority](terminology.md#supermajority) of [ledger votes](terminology.md#ledger-vote) with a ledger interpretation that matches the leader's.
Some number of epochs after stake has been deactivated while it progressively becomes available for withdrawal. During this period, the stake is considered to be "deactivating". More info about: [warmup and cooldown](implemented-proposals/staking-rewards.md#stake-warmup-cooldown-withdrawal)
A preimage resistant [hash](terminology.md#hash) over the final contents of an entry, which acts as the [entry's](terminology.md#entry) globally unique identifier. The hash serves as evidence of:
The fee account in the transaction is the account pays for the cost of including the transaction in the ledger. This is the first account in the transaction. This account must be declared as Read-Write (writable) in the transaction since paying for the transaction reduces the account balance.
The smallest unit of a [program](terminology.md#program) that a [client](terminology.md#client) can include in a [transaction](terminology.md#instruction).
A sequence of [validator](terminology.md#validator) [public keys](terminology.md#public-key). The cluster uses the leader schedule to determine which validator is the [leader](terminology.md#leader) at any moment in time.
A [hash](terminology.md#hash) of the [validator's state](terminology.md#bank-state) at a given [tick height](terminology.md#tick-height). It comprises a validator's affirmation that a [block](terminology.md#block) it has received has been verified, as well as a promise not to vote for a conflicting [block](terminology.md#block) \(i.e. [fork](terminology.md#fork)\) for a specific amount of time, the [lockout](terminology.md#lockout) period.
A type of [client](terminology.md#client) that can verify it's pointing to a valid [cluster](terminology.md#cluster). It performs more ledger verification than a [thin client](terminology.md#thin-client) and less than a [validator](terminology.md#validator).
The duration of time for which a [validator](terminology.md#validator) is unable to [vote](terminology.md#ledger-vote) on another [fork](terminology.md#fork).
A weighted [credit](terminology.md#credit) in a rewards regime. In the validator [rewards regime](cluster/stake-delegation-and-rewards.md), the number of points owed to a stake during redemption is the product of the [vote credits](terminology.md#vote-credit) earned and the number of lamports staked.
A stack of proofs, each which proves that some data existed before the proof was created and that a precise duration of time passed before the previous proof. Like a [VDF](terminology.md#verifiable-delay-function), a Proof of History can be verified in less time than it took to produce.
A [block](terminology.md#block) or [slot](terminology.md#slot) that has reached maximum [lockout](terminology.md#lockout) on a validator. The root is the highest block that is an ancestor of all active forks on a validator. All ancestor blocks of a root are also transitively a root. Blocks that are not an ancestor and not a descendant of the root are excluded from consideration for consensus and can be discarded.
A synthetic [account](terminology.md#account) provided by the runtime to allow programs to access network state such as current tick height, rewards [points](terminology.md#point) values, etc.
The number of [confirmed blocks](terminology.md#confirmed-block) since the transaction was accepted onto the [ledger](terminology.md#ledger). A transaction is finalized when its block becomes a [root](terminology.md#root).
A full participant in the [cluster](terminology.md#cluster) responsible for validating the [ledger](terminology.md#ledger) and producing new [blocks](terminology.md#block).
A function that takes a fixed amount of time to execute that produces a proof that it ran, which can then be verified in less time than it took to produce.
Some number of epochs after stake has been delegated while it progressively becomes effective. During this period, the stake is considered to be "activating". More info about: [warmup and cooldown](cluster/stake-delegation-and-rewards.md#stake-warmup-cooldown-withdrawal)
