While Bitcoin and Cryptocurrency may have been the first widely known uses of Blockchain technology today, it's far from the only one. In fact, blockchain is revolutionizing every industry. Blockchain is the biggest technological breakthrough since the internet and becomes the most darling topic in the tech sense. The blockchain is ledger that allows all members to record transactions on system so that they are stored safely, secure and incorruptible.
Blockchain is software that fosters peer-to-peer relationships. For instance, if a published account insufficiently explains a methodology, any peer can review the process and see how the results were obtained.
The ledger's transparent channels can help anyone know what data is reliable for use, where it came from, how to store it, who does the update and how to use it in an ethical manner. Simply put, it's possible to trace data on a distributed digital ledger from the entry point to the exit.
If you are a complete beginner, I would suggest starting off with Bitcoin. Try to understand what Bitcoin is and how it works then you can dive in into more complex topics. This is one of my favourite videos on the subject:
While reading about blockchain as a technology, you will probably encounter many technology related terms like blocks, mining, proof of work, proof of stake, smart contracts, hashing, etc. You will need a Glossary.
As a next step, I would suggest creating a wallet and playing with the software sending transactions back and forth. This way you get to interact with the Bitcoin blockchain. Start off with $10 USD you don't need to buy a whole Bitcoin. You will learn about addresses, backups and private keys. A great wallet for beginners is Copay.
An excellent source of information is the Bitcoin whitepaper published in 2008 by Satoshi Nakamoto. Read the paper couple of times and try to understand it. This is where all started. Here is another link explaining the blockchain technology: Blockchain Intro.
If you are a developer or have a technical understanding of the blockchain, you can watch the video by Andreas M. Antonopoulos about the Bitcoin blockchain, consensus rules, hashing, etc.
There are different types of blockchains:
Public(Bitcoin is a public blockchain)
Private, consortium blockchains and hybrid blockchains.
After getting an understanding about Bitcoin, you could start exploring other blockchains like Ethereum, Zcash, Dash, Monero etc. Find a list of all publicly listed blockchains here and read the whitepapers on their websites. Join their communities on Reddit or Slack, read the news and with the time you will get the big picture.
Thus, the blockchain is a ledger that allows all members to record transactions on system so that they are stored safely, secure and incorruptible.