Introduction to Blockchain

Learn about the blockchain and commonly used terms.

Let’s very briefly look at some types and examples of blockchains. We’ll also learn some common terms used when discussing blockchains and the cryptosphere, an informal term used to describe the crypto community.

Introducing the blockchain

A blockchain is a distributed database or ledger that stores a complete record of transactions. It serves as a database for information on electronic transactions with an immutable cryptographic signature called a hash. Blockchains store this information in a way that makes it almost impossible to modify, alter, hack, or cheat the system. The information is public and transparent; anyone can view, but not modify, every transaction. This provides a level of trust, so no third party is needed to verify the transactions.

Each block in the chain is made up of a number of transactions, and every time a new transaction occurs, a record is added to the ledger of each participant. That means if a hacker or other entity wanted to tamper with a block and its recorded transaction, they would have to modify every block in the chain across all the distributed versions and nodes.

Applications of blockchains

The most widespread use of blockchains is in cryptocurrencies and non-fungible tokens (NFTs), the most common of which is Bitcoin. There has been an explosion of other blockchain platforms recently, including:

  • Ethereum

  • Solana

  • Ripple

  • Avalanche

  • Tron

  • Binance Smart Chain

These platforms have different implementations, the most central of which are the storage and verification of monetary transactions. Non-monetary use cases of blockchains include healthcare, banking and finance, supply chains, gaming, copyright and royalties protection, data sharing, identity management, and voting.

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Common blockchain terms

Let’s take a look at some of the most common terms and abbreviations used when discussing blockchains.


The term dApp stands for decentralized application. This is basically an application that runs on a blockchain platform or a peer-to-peer (P2P) blockchain network rather than on a single computer. A dApp could be referred to as an application that has one or more blockchain platforms (for example, Ethereum, Solana, Polka) as a backend.


Web3 can be considered an idea for a new version of the World Wide Web. It encompasses concepts such as decentralization, blockchain technologies, and token-based economics. Web3 is a better, modified version of the current web that has decentralization at its core.


An application programming interface (API) creates a connection between a blockchain and another piece of software, allowing developers to interact with the blockchain. Common examples of blockchain APIs include Chain API, BlockCypher API, and Coinbase API.


A distributed ledger technology (DLT) is a decentralized database managed by multiple participants across multiple nodes. In our case, it’s another term for blockchain.

This is only a sample of basic applications and terms; blockchains are a much broader topic than we can cover in the scope of this course. If you’re interested in conducting some additional research, that will help you in your future blockchain projects.