Blockchain is simply a distributed database that is shared among all the participants of the network. This technology aims at solving a few problems.
The key innovation between a blockchain database and a typical database is how the information is structured. Blockchain gathers information together in “blocks”. These blocks can hold a certain amount of data, once the block filled, it is closed and linked to the previously filled block. the blocks of data linked to each other is hence why it is known as blockchain; because of this block and chain structure.
A few more details about blockchain:
Each block is given a time stamp when it is added to the chain.
Blockchain creates an irreversible timeline of events, which cannot be changed after the fact.
Now in the context of cryptocurrencies, blockchain technology is implemented with a decentralized goal in mind
Here’s a quick rundown of how a cryptocurrency system works
Blockchain is simply a specific type of database structure. Data is put into a block and once that block is finalized, it is linked to the previous block hence the chain feature. The advantage that it is most known for is solving the double spending problem. In other words Blockchain is the first database in which you can have verifiably unique digital assets which cannot be replicated or "spent twice" This solved one of the major hurdles for creating digital money.