Read the original article: Simplified Blockchain Part One: Theory
Blockchain in Two Words
You can interpret blockchain as a distributed database, each node of which is launched on the client side. All nodes synchronize (validate and confirm) all transactions among themselves. Every deployed smart contract (code and variables) stays there forever with its unique id. Initially, blockchain was created as a way to store information about sending/receiving money between clients. New blockchain systems are significantly different — they let users deploy and execute functions + variables, also known as smart contracts. Smart contracts turned these databases into real, stateful servers.
Classical Server vs Blockchain Network
To simplify your understanding of blockchain, check out the figure and table below:
Read the original article: Simplified Blockchain Part One: Theory