A fork is a divergence in blockchain rules or history, from software upgrades to chain splits.
Soft forks tighten rules in a backward-compatible way. Hard forks create incompatible rule sets and can split assets.
In research workflows, Fork is usually interpreted with Hard fork, Soft fork, Mainnet, and Governance token rather than as a standalone signal. Throughput, finality, and fee markets determine user experience and where activity migrates during congestion.