What is Bitcoin ?

(from Wikipedia )

Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoin as payment.Bitcoin can also be held as an investment. According to research produced by Cambridge University in 2017, there are 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using bitcoin.

Hahhh !! What is  'Blockchain' ?? ( from Investopedia )

A blockchain is a digitized, decentralized, public ledger of all cryptocurrency transactions. Constantly growing as ‘completed’ blocks (the most recent transactions) are recorded and added to it in chronological order, it allows market participants to keep track of digital currency transactions without central recordkeeping. Each node (a computer connected to the network) gets a copy of the blockchain, which is downloaded automatically. Originally developed as the accounting method for the virtual currency Bitcoin, blockchains – which...