Improve terminology page (#18441)

Co-authored-by: Gregg Dourgarian <greggd@aidacreative.com>
Co-authored-by: Haskell FTW <HaskellFTW@protonmail.com>

docs/src/terminology.md

@@ -6,7 +6,18 @@ The following terms are used throughout the documentation.
 
 ## account
 
-A persistent file addressed by [public key](terminology.md#public-key) and with [lamports](terminology.md#lamport) tracking its lifetime.
+A record in the Solana ledger that either holds data or is an executable program.
+
+Like an account at a traditional bank, a Solana account may hold funds called [lamports](terminology.md#lamport). Like a file in Linux, it is addressable by a [key], often referred to as a (terminology.md#public-key) public key or pubkey.
+
+The key may be one of:
+an ed25519 public key
+a program-derived account address (32byte value forced off the ed25519 curve)
+a hash of an ed25519 public key with a 32 character string
+
+## account owner
+
+The address of the program that owns the account. Only the owning program is capable of modifying the account.
 
 ## app
 
@@ -22,7 +33,7 @@ A contiguous set of [entries](terminology.md#entry) on the ledger covered by a [
 
 ## blockhash
 
-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
+A unique value ([hash](terminology.md#hash)) that identifies a record (block).  Solana computes a blockhash from the last [entry id](terminology.md#entry-id) of the block.
 
 ## block height
 
@@ -30,15 +41,19 @@ The number of [blocks](terminology.md#block) beneath the current block. The firs
 
 ## bootstrap validator
 
-The first [validator](terminology.md#validator) to produce a [block](terminology.md#block).
+The [validator](terminology.md#validator) that produces the genesis (first) [block](terminology.md#block) of a block chain.
+
+## BPF loader
+
+The Solana program that owns and loads (BPF) smart contract programs, allowing the program to interface with the runtime
 
 ## CBC block
 
-Smallest encrypted chunk of ledger, an encrypted ledger segment would be made of many CBC blocks. `ledger_segment_size / cbc_block_size` to be exact.
+The smallest encrypted chunk of ledger, an encrypted ledger segment would be made of many CBC blocks. `ledger_segment_size / cbc_block_size` to be exact.
 
 ## client
 
-A [node](terminology.md#node) that utilizes the [cluster](terminology.md#cluster).
+A computer program that accesses the Solana server network [cluster](terminology.md#cluster).
 
 ## cluster
 
@@ -50,7 +65,7 @@ The wallclock duration between a [leader](terminology.md#leader) creating a [tic
 
 ## 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.
+A [block](terminology.md#block) that has received a [supermajority](terminology.md#supermajority) of [ledger votes](terminology.md#ledger-vote).
 
 ## control plane
 
@@ -64,9 +79,9 @@ Some number of [epochs](terminology.md#epoch) after [stake](terminology.md#stake
 
 See [vote credit](terminology.md#vote-credit).
 
-## cross-program invocation
+## cross-program invocation (CPI)
 
-An [instruction](terminology.md#instruction) called from within an instruction. Put differently, it is how a program calls into another program. For more information, see [calling between programs](developing/programming-model/calling-between-programs.md).
+A call from one smart contract program to another. For more information, see [calling between programs](developing/programming-model/calling-between-programs.md).
 
 ## data plane
 
@@ -88,7 +103,7 @@ A preimage resistant [hash](terminology.md#hash) over the final contents of an e
 - The specified [transactions](terminology.md#transaction) are those included in the entry
 - The entry's position with respect to other entries in [ledger](terminology.md#ledger)
 
-See [Proof of History](terminology.md#proof-of-history).
+See [proof of history](terminology.md#proof-of-history).
 
 ## epoch
 
@@ -128,11 +143,11 @@ See [cross-program invocation](terminology.md#cross-program-invocation).
 
 ## instruction
 
-The smallest unit of a [program](terminology.md#program) that a [client](terminology.md#client) can include in a [transaction](terminology.md#transaction). Within its processing code, an instruction may contain one or more [cross-program invocations](terminology.md#cross-program-invocation).
+The smallest contiguous unit of execution logic in a [program](terminology.md#program). An instruction specifies which program it is calling, which accounts it wants to read or modify, and additional data that serves as auxiliary input to the program. A [client](terminology.md#client) can include one or multiple instructions in a [transaction](terminology.md#transaction). An instruction may contain one or more [cross-program invocations](terminology.md#cross-program-invocation).
 
 ## keypair
 
-A [public key](terminology.md#public-key) and corresponding [private key](terminology.md#private-key).
+A [public key](terminology.md#public-key) and corresponding [private key](terminology.md#private-key) for accessing an account.
 
 ## lamport
 
@@ -195,15 +210,19 @@ The private key of a [keypair](terminology.md#keypair).
 
 The code that interprets [instructions](terminology.md#instruction).
 
+## program derived account (PDA)
+
+An account whose owner is a program and thus is not controlled by a private key like other accounts.
+
 ## program id
 
 The public key of the [account](terminology.md#account) containing a [program](terminology.md#program).
 
-## Proof of History
+## proof of history (PoH)
 
 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.
 
-## public key
+## public key (pubkey)
 
 The public key of a [keypair](terminology.md#keypair).
 
@@ -215,6 +234,10 @@ A [block](terminology.md#block) or [slot](terminology.md#slot) that has reached
 
 The component of a [validator](terminology.md#validator) responsible for [program](terminology.md#program) execution.
 
+##Sealevel
+
+Solana's parallel smart contracts run-time.
+
 ## shred
 
 A fraction of a [block](terminology.md#block); the smallest unit sent between [validators](terminology.md#validator).
@@ -239,11 +262,15 @@ Collectively, slots create a logical clock. Slots are ordered sequentially and n
 
 ## smart contract
 
-A set of constraints that once satisfied, signal to a program that some predefined account updates are permitted.
+A program on a blockchain that can read and modify accounts over which it has control.
 
 ## sol
 
-The [native token](terminology.md#native-token) tracked by a [cluster](terminology.md#cluster) recognized by the company Solana.
+The [native token](terminology.md#native-token) of a Solana [cluster](terminology.md#cluster).
+
+## Solana Program Library (SPL)
+
+A library of programs on Solana such as spl-token that facilitates tasks such as creating and using tokens
 
 ## stake
 
@@ -255,7 +282,7 @@ Tokens forfeit to the [cluster](terminology.md#cluster) if malicious [validator]
 
 ## sysvar
 
-An [account](terminology.md#account) maintained by the runtime and provided to programs which provide cluster state such as current tick height, rewards [points](terminology.md#point) values, etc.  Sysvars can either be [passed to the program as an account or queried by the program via a syscall](developing/runtime-facilities/sysvars.md).
+A system [account](terminology.md#account).  [Sysvars](developing/runtime-facilities/sysvars.md) provide cluster state information such as current tick height, rewards [points](terminology.md#point) values, etc.  Programs can access Sysvars via a Sysvar account (pubkey) or by querying via a syscall.
 
 ## thin client
 
@@ -271,7 +298,7 @@ The Nth [tick](terminology.md#tick) in the [ledger](terminology.md#ledger).
 
 ## token
 
-A scarce, fungible member of a set of tokens.
+A digitally transferable asset.
 
 ## tps
 
@@ -279,7 +306,7 @@ A scarce, fungible member of a set of tokens.
 
 ## transaction
 
-One or more [instructions](terminology.md#instruction) signed by the [client](terminology.md#client) using one or more [keypairs](terminology.md#keypair) and executed atomically with only two possible outcomes: success or failure.
+One or more [instructions](terminology.md#instruction) signed by a [client](terminology.md#client) using one or more [keypairs](terminology.md#keypair) and executed atomically with only two possible outcomes: success or failure.
 
 ## transaction id
 
@@ -295,13 +322,13 @@ A set of [transactions](terminology.md#transaction) that may be executed in para
 
 ## validator
 
-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 full participant in a Solana network [cluster](terminology.md#cluster) that produces new [blocks](terminology.md#block).  A validator validates the transactions added to the [ledger](terminology.md#ledger)
 
 ## VDF
 
 See [verifiable delay function](terminology.md#verifiable-delay-function).
 
-## verifiable delay function
+## verifiable delay function (VDF)
 
 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.
 
@@ -315,7 +342,7 @@ A reward tally for [validators](terminology.md#validator). A vote credit is awar
 
 ## wallet
 
-A collection of [keypairs](terminology.md#keypair).
+A collection of [keypairs](terminology.md#keypair) that allows users to manage their funds.
 
 ## warmup period