Definition

A shared, immutable ledger network records all XRP (or other cryptocurrencies) transactions kept up to date by many computers, miners, and nodes.

Blockchain used in a sentence

• “We can look at the blockchain and see proof of what’s going on.” 
• “Only pseudonymous XRP addresses are tracked on the Blockchain. This excludes individuals’ true names or other identifying information.” 
• “Every transaction executed is recorded in a ledger known as the blockchain, kept by each currency owner keeps, and the ledger is updated every time a transaction is done.” 

History of the term “Blockchain.”

In his 1982 dissertation “Computer Systems Established, Maintained, and Trusted by Mutually Suspicious Groups,” cryptographer David Chaum presented a blockchain-like protocol for the first time. 

Stuart Haber and W. Scott Stornetta described their work on a cryptographically secure chain of blocks in 1991. They sought to create a system that prevented tampering with document timestamps. The term “Block” gets introduced.

In 2008, Satoshi Nakamoto created bitcoin, the first practical application of blockchain technology. That technology, however, is based on concepts from the 1990s. In the bitcoin white paper’s footnotes, Nakamoto also mentions it.