# Hive Developer Portal - Glossary

Understanding the common terms used by the Hive blockchain is an important part of being able to build applications and tools that use it.

This section outlines several of the common terms.

More terms and information can be found on the hive.blog FAQ.

### Chain Basics

Blockchain
  Decentralized ledger and consensus protocol
Hive (blockchain)
  Name of the blockchain and platform
Bandwidth
  formerly the limit of data each account can send/use (replaced by Resource Credits)
Resource Credits
  is the limit of data each account can utilize resources on the blockchain (also known as RC)
VESTS
  The fundamental unit of accounting that Hive Power is derived from
HIVE (currency)
  Currency of the blockchain, liquid version of Hive Power
HBD
  Hive Backed Dollar, $1 worth of Hive
Hive Power
  Locked version of HIVE which gives account influence on the platform
Transaction
  Operations/Activity/Write requests to the blockchain. A transaction is a submitted update to the Hive blockchain. This can include token transfers, posts/comments, votes, etc.
Block
  Every three seconds, the Hive blockchain produces a new block. Each time a new block is produced, the distributed network is updated with all of the transactions that occurred within that block.
Block Header
  Information about block, root, and witness who signed, etc.
Price feed
  Feed that is maintained by witnesses to ensure HBD/HIVE price stability
Account
  An account is a container for all of the activity associated with a particular user's wallet on the blockchain. This includes all of their tokens, posts, comments, upvotes, transfers, etc.
Authority
  Each Account has multiple authority and keys to manager different permissions on the platform
Owner
  Owner authority/permission of a given account
Key
  Keys are used to authenticate transactions. Each key contains a public/private pair. When a transaction is submitted to the Hive blockchain, it is signed by the account owner using their private key. The blockchain is able to determine that the transaction is valid by validating the signature against the public key from the pair.
Public Key
  Public key of account's certain authority
Private Key
  Private key to sign a transaction with account's authority, should be kept secret because it grants access to account
Wif
  Wallet Import Format/Private key, should be kept secret because it grants access to account
Active key
  The active key is used to make transfers and place orders in the internal market
Posting key
  The posting key is used for posting and voting
Owner key
  The owner key is the master key for the account and is required to change the other keys
Post
  A post is a root level comment - one that has no "parent".
Comment
  A comment is text content that is stored on the blockchain. Comments can be linked to other comments as "replies" through parent/child relationships.
Vote
  A vote is an expression of like (upvote) or dislike (downvote) for a post/comment. The Hive blockchain uses the votes that a post/comment has received to determine its share of the rewards.
Reputation
  Account's reputation on the platform
Markdown language
  Easy to read and write, plain text format language commonly used to create Hive articles
Permlink
  Unique identifier of every comment or post of an author, within the context of that author. ('@author/permlink' combos are globally unique)
Mainnet
  The 'production' Hive blockchain network wherein real HIVE is held and actual transactions take place.
Delegation
  The assignment of Hive Power for content influence by another account (cannot be spent, can be revoked by the delegator in 5 days)
PowerUp
  Convert HIVE to Hive Power and vice-versa with PowerDown
Reward Pool
  Every day, a fixed amount of HIVE tokens are allocated to the network reward fund, commonly called the "reward pool." These get distributed to authors and curators for posting and voting on content.
AppBase
  Plug-in architecture that provides a robust foundation for scaling. It enables many components of the Hive blockchain to become modular by creating additional non-consensus blockchains as dedicated plugins.
RocksDB
  A fast-on-disk data store with an advanced caching layer, which minimizes latency when reading/writing to and from disk.
MIRA
  Multi Index Rocksdb Adapter that updates the database backend of Hive from memory mapped files to a disk log-structured merge-tree implemented via the RocksDB library.
Manabar

  Tracked voting power that is regenerated from 0 to 100% of max linearly over 5 days. It is a function of Hive Power, delegations, and active power down that tracks unspent reward fund shares.

  Each user also has a manabar specifically for downvotes, which is 25% of the upvote manabar. Downvotes will consume this mana first before consuming regular mana. When voting, 1/50th of the remaining mana is used for a 100% vote. The same math is used for downvote mana but multiplied by 4 because the downvote manabar is 25% the size of the normal manabar. The maximum of these values is used. When both manabars are at 100%, the values are the same. When downvote mana runs out, normal mana is then used.

Reverse Auction
  The window of 5 minutes where curation rewards are sent back to reward pool.
DHF
  Also known as Decentralized Hive Fund. An on-chain decentralized autonomous organization (DAO) that allows users to submit proposals for funding and use stake weighted voting to select which proposals should be funded.

### Governance

DPOS
  Delegated Proof of Stake
Proxy
  The assignment of Hive Power for DPOS governance and DHF approval by another account (cannot be spent, can be revoked instantly)
Node
  A node is an instance of the Hive blockchain running on a server.
Witness
  Witness is a position/role for the people who are chosen by community (delegate trust) to support platform and run consensus protocol to ensure security and validity of transactions/blocks on the blockchain. A witness is responsible for signing and validating blocks for the Hive blockchain.
Hardfork
  Process to release protocol/blockchain consensus upgrades
Softfork
  Process to release protocol/blockchain software improvements
Witness Vote
  Voting/electing witnesses with account's stake
DAO
  Decentralized Autonomous Organization (see: DHF).
HBD Haircut
  Rules to stop printing HBD when the supply is too high. Note: HBD printing for the DHF (@steem.dao) does not follow these rules and will continue to print HBD regardless of the supply.

### Transactions

P2P
  The peer-to-peer network is how transactions are broadcasted to mempool until they are included in a block.
Mempool
  Where a transaction that is being conducted over the p2p network is transmitted and held until a witness picks it up and includes it in the next block.
Pending Transaction
  Transaction that is pending and to be included to the blockchain
Transaction Hex
  Hash of the transaction
Signatures
  Transaction signature signed by an account with a private key
Canonical Signatures
  Reduce entropy Signatures that follow the BIP-0062 specification to prevent transaction malleability. All Signatures on Hive are Canonical Signatures, since 0.20.2.
Broadcast Transaction
  Event where a signed transaction is broadcasted to the p2p network so that witnesses could validate and include in a block
Virtual operation
  Operations that are derived from blockchain activity, but aren't actually stored as operations themselves (ex. curation and author rewards). They happen based on consensus from the blockchain based on other normal operations

### API

Trending
  Posts/Discussions that are highly valued by the community with bigger time interval update
Hot
  Posts/Discussions that are highly valued with shorter time interval update
Feed
  Posts/Discussions from followers of a particular account
Active
  Posts/Discussions that are still actively being engaged
New
  Newly created posts
Cashout
  Posts which was paid out recently
Promoted
  Posts which was promoted by burning HBD to get more visibility
Pending Payout
  Estimated pending payout for blog posts/comments
Tags
  A tag is a descriptor that is used to identify the type of content contained within a comment/post.
Trending Tags
  Mostly used tags
Following
  Account that is being followed
Follower
  Account that is following the user
State
  State of blockchain for path - accounts/tags/filters/posts
Dynamic Global Properties
  Current blockchain global properties in play for each block
Median Price
  Median Price feed provided by all witnesses
Curator
  A Hive user who upvotes a post by using their daily voting power to assign value to a post that they believe has good quality content and should be seen and the author rewarded
Curation reward
  The reward given to a curator, which is their portion of the 50% allocated to all curators that have upvoted a post
Reblog
  Re-posting another author's post in your blog feed for your followers list

### Market

Conversion Requests
  Request submitted for Converting HBD to HIVE
Order Book
  Internal market order book to exchange HBD <-> HIVE
SMT
  Smart Media Tokens
Limit Order
  A direction given to the DEX to buy or sell an asset at a specified price or better, that expire within 30 days of creation.