Blockchain: A cryptographically protected distributed ledger made up of blocks that contain transaction history. As the blocks are linked to one another, it is not possible to alter older blocks.
Address: Sort of like a bank account, you can share your coin-specific address so somebody can send coins to you over the Blockchain.
Wallet: A cryptocurrency wallet stores private and public keys, which are necessary to send and receive coins. There are hardware (cold wallets) , software and paper wallets.
Bitcoin: The first digital currency to have been tested together with the invention of Blockchain and the first one to solve the double-spending without the need of a trusted authority or centralised server.
Altcoin: Short for alternative coin, the term is commonly used to describe any cryptocurrency other than Bitcoin.
Initial Coin Offering (ICO): An ICO (the equivalent to an IPO in the crypto space), also known as a token sale, is a means of crowdfunding where a company sells a new coin or token. Typically, the funds they received are used to develop the new concept, and the token they issued will be used to transact in their ecosystem once it is launched.
Ethereum: Ethereum is the second generation of Blockchain after the first Bitcoin Blockchain technology. Smart contracts can be easily coded of the Ethereum Blockchain which is different from the Bitcoin Blockchain. The smart contracts can be used in real-life processes.
Smart Contract: An agreement that is written and communicates with the Blockchain (computer code) and automatically executes when certain conditions are met.
Double-spending: is a potential flaw in a digital cash scheme in which the same single digital token can be spent more than once. As with counterfeit money, such double-spending leads to inflation by creating a new amount of copied currency that did not previously exist.