Bitcoin
Bitcoin is Peer-to-Peer Electronic Cash System that sparked the cryptocurrency revolution.
See major Bitcoin website: https://bitcoin.org/en/
The bitcoin-paper was released a few months before the network started. The author published under a psuedonym. The inventor is unknown.
As of January 2021, Bitcoin has the highest marketshare of the cryptocurrency market. This can be shown by the Bitcoin Dominance percentage. As of November 20, 2020, coinmarketcap.com listed the Bitcoin Dominance as 66%.
In the cryptocurrency context, Bitcoin is the money (i.e. used as a numéraire).
The Bitcoin network of P2P nodes maintains a blockchain.
The changes to the Bitcoin blockchain can be seen using an explorers. Here is an example: Bitcoin Block Explorer.
An individual uses a wallet to store Bitcoin and make transactions. An individual makes transactions on the Bitcoin network by using a private cryptographic key.