## 1. What is blockchain?
Blockchain is a chain of blocks linked by cryptography. Commonly referred to as a type of distributed ledger.
## 2. What is Ethereum?
Ethereum is a publicly available and open-source blockchain that features smart contracts.
According to Ethereum.org:
"Ethereum is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of downtime, censorship, fraud or third-party interference."
## 3. What are Smart Contracts?
Smart contracts are computational pieces that run on a blockchain.
According to Nick Szabo, who coined the term:
"A smart contract is a computerized transaction protocol that executes the terms of a contract."
## 4. What is Solidity?
Solidity is the most famous programming language used to program smart contracts for the Ethereum blockchain.
According to Solidity.readthedocs.io:
"Solidity is a contract-oriented, high-level language for implementing smart contracts."
## 5. What is Metamask?
MetaMask is a browser extension that serves as a bridge between the browser and decentralized applications by handling wallets, accounts and transaction signing.
According to Metamask.io:
"MetaMask is a bridge that allows you to visit the distributed web of tomorrow in your browser today. It allows you to run Ethereum dApps right in your browser without running a full Ethereum node."