A smart contract is a computer program or a transaction protocol respectively, which is intended to automatically execute, control or document respectively legally relevant events and actions according to the terms of a contract, of an agreement or of a negotiation.
DAO is an abbreviation of ‘Decentralised Autonomous Organization’. This is basically an organisation that runs automatically on itself without any human interventions. The work is automatically excecuted through Smart contracts.
An airdrop is a way to distribute coins. End users can generally get coins for free or in exchange for a small task, such as subscribing to a newsletter, sending a tweet or inviting other people via a personal affiliate link.
Bitcoin is a digital or virtual cryptocurrency created in 2009 that uses peer-to-peer technology to facilitate instant payments.
With digital currency, there is a risk that the holder could make a copy of the digital token and send it to a merchant or another party while retaining the original.
A block explorer is an online service to track blockchain transactions. It usually is a website where you can see all the new blocks that are being created. You can also search for transactions and wallet addresses. The best-known block explorers are blockchain.info for Bitcoin and etherscan.io for Ethereum.