• Address/Key; Public & Private: To send crypto you need the public address as a destination, and to send crypto from a wallet you need the private address in order to access the funds within the wallet. The private address is the "key" to using the wallet. The public address is the "key" needed to have a destination for sending funds.
  • Altcoin/Token: They are not one of the major cryptocurrencies or crypto-utilities but can be on the same ledger.
  • Block: A forever sealed section of the blockchain, containing transactions that occurred. For many cryptos the transactions on any given block are only those from the time when a new crypto "coin" was being minted; which can take second to hours depending on the crypto.
  • Blockchain: The entirety of blocks, which is chronological and immutable. Only the last unfinished block can contain new ledger changes until it is sealed, and no previous block can be changed. 
  • BTC: Short for Bitcoin; ETH = Ethereum, ETC = Ethereum classic, LTC = LiteCoin, list of prices and short spellings can be found at CoinCapMarket.
  • Burned: Sent to a wallet with an unknown to all private key.
  • Cryptocurrency: Based on blockchain technology, and decentralized. They are only used for representing value.
  • Crypto-utility: Similar to a cryptocurrency but have purposes beyond a simple value representation such as smart contracts, virtual computing, decentralized file storage, independent tokens on the same network, etc. They typically have a value and it may be tied to their use as "gas" for the network, as those using it may only be using their own private token.
  • Crypto: Short for all cryptocurrencies and crypto-utilities. Can be short for representation of any units of cryptocurrencies, crypto-utilities, and tokens.
  • Decentralized: With cryptos this refers to the network that keeps the ledger (blockchain) being spread out, typically globally. All the different entities must be in agreement at all times to continue operating, without creating a fork. Due to the global nature of many many machines operating, consensus for illegitimate changes to the ledger are effectively impossible. Changes would require people to agree from all over the globe, protecting the interest of the crypto itself if it has incentivization through POW/POS/POP.
  • Double spending: When currency, including virtual & crypto-utilities, record money that does not exist. For example one bank says they send another bank $10, but does not record that they send $10. The problem potential exists when not every $1 or item is represented by a physical object; which is true of the majority of fiat in the world.
  • Exchange: A place that allows trading of traditionally stocks for stocks & fiat, but now also includes cryptos for cryptos a& cash. They typically have some fees, and traditional stock exchanges have lots of regulation, stipulation, etc etc... where as Crypto exchanges are often open use to all.
  • Fiat: The legal tender in any country. Commonly known as physical coins & cash, but includes values designated by systems of the country to exist on bank ledgers and other entities that don't need the physical representation.
  • Fork: When a crypto holds the original blockchain but after the "fork" there are different blockchains much like a fork in the road has two paths. Two different "roads" emerge, and at least one takes on a new name. For example Ethereum and Ethereum classic have the same blockchain up until a certain date where they split and became two different ledgers, effectively creating ETC and ETH. They do not interact other than they share a common immutable ledger, and both could use the common ledger but neither are required to beyond the fork. Each fork direction can become whatever the miners/nodes decide on collectively.
  • Gas: The cost to change a the ledger. Paid for by an amount of the crypto. Example, it cost me X amount of Ethereum to have a transaction processed where I send Ethereum or an Ethereum token to another wallet.

    Some cryptos incentivize processing of ledger transactions by offerings gas to a node/miner. Often the amounts are decided upon by consensus of everyone running the crypto ledger as a node/miner. In other cases the nodes/miners decided on the amount of gas to be permantely burned per transaction.

    Different cryptos may incentivize order of processing ledger changes based on the amount of gas paid. For example if changing the ledger on a crypto that does this, I can pay more to have it happen faster.
  • Genesis block/wallet: The first block, including the first wallets and first ledger changes, in a blockchain.
  • Hodl: The correct word to describe describe when you do not sell or trade cryptos you own, particularly when there is volatility showing. Example, "You are hodling Bitcoin even when the price dips to $2800, because you know it'll go up"
  • Mining: Also know as POW; proof of work. Computational work is performed to solve ever increasingly difficult algorithms. The person/s to finish first gets rewarded as a new crypto is minted and given to them for their work. At the same time they record all ledger changes in the unfinished block, and it is finished & sealed when the POW is done needed to mint a new crypto. The seal is partially protected by the need to perform the POW to ever change anything in the block again, on top of needing all others with the ledger to agree to the changes. (effectively immutable unless the world wants to change it)

    Typically all mining is done by "pools". In order to gain a competitive edge miners group together and split the effort as well as the reward. Each and everyone in the pool has the ledger, and would also be needed to change it on top of all the other pools and nodes. No one single miner would be able to perform the POW again in a reasonable amount of time.
  • MSB: Money service business. MSB's are under a lot of regulations because they typically transfer virtually represented fiat money and could be prone to double spending since they don't use cryptos (hence the regulation).
  • Node: A very broad term for computers & devices that actively run and record a crypto ledger. There are variances such as validators & POS nodes.

    Nodes can do but are not limited to: Run along side miners for more decentralized record keeping, get rewarded for processing transactions, have votes on changes in the network, mint cryptos by processing transactions, charge gas for processing, validate other nodes processing work, and probably many undiscovered uses.
  • Paper wallet: A piece of paper with a written public key &/or private key, possibly QR codes representing both/either public & private keys, of a crypto wallet.
  • POW/POS/POP: Proof of work is done by mining. Proof of stake is when a node "stakes" a certain amount of the crypto it runs in order to get a reward from processing ledger changes. Proof of processing is when nodes get rewards for processing ledger changes.
  • QR code: A scan-able image typically by smartphones that holds information such as GPS coordinates, part numbers, or crypto addresses.
  • Satoshi Nakamoto: Claimed name by the inventor of Bitcoin. True name and person-hood has not been authenticated, even if it is Satoshi Nakamotor.
  • Wallet: A piece of the ledger that can hold cryptos, accessible with the private key. Some crypto wallets can also hold tokens.