A rollup executes transactions off L1 execution and posts data or proofs back to a parent chain.
Rollups aim to multiply throughput while keeping settlement anchored to L1 security.
In research workflows, Rollup is usually interpreted with Layer 2, Optimistic rollup, ZK rollup, and Data availability rather than as a standalone signal. Throughput, finality, and fee markets determine user experience and where activity migrates during congestion.