A security model for certain layer 2 solutions where, to increase speed, transactions are rolled up into batches and submitted to a blockchain in a single transaction. The transaction computation is done off-chain and then supplied to the main chain with a proof of their validity. This method increases the amount of transactions possible while maintaining security.
It is most commonly applied to Ethereum and the other Ethereum Virtual Machines (EVMs). This is tied to Zero Knowledge Rollups. The hope is this will all help to scale the Ethereum chain.