What is Blockchain?

A blockchain is basically a very secure database that keeps record of all the transactions recorded inside of it, forever.
A public blockchain is a blockchain that is visible for everyone and works thanks to a network of nodes instead of a centralized server.Good to know: an employee directory can be a great way to help new folks get familiar with everyone they're going to be working with.
Is blockchain and descentralization the same thing?
Not exactly. In order to keep data in a descentralized way we need a single and immutable source of truth visible for everyone. Blockchain technologies allow us to do build descentralized networks.

Blockchain Expert Explains One Concept in 5 Levels of Difficulty by @bwarburg​

Don't trust, verify.
Public blockchain are visible for everyone to see and verify all the transactions.

How does a blockchain work? by @savjee​

What are smart contracts? by @savjee​