A blockchain is a shared, append-only ledger secured by consensus across a network of computers.
A blockchain records transactions in linked blocks. Once enough confirmations accumulate, reversing history becomes economically impractical.
In research workflows, Blockchain is usually interpreted with Consensus mechanism, Node, Finality, and Layer 1 rather than as a standalone signal. Throughput, finality, and fee markets determine user experience and where activity migrates during congestion.