What is a memory pool in crypto?

A memory pool or mempool can be perceived as a form of a waiting area before a transaction is taken by a miner and recorded in a block. Transactions are sent on the network between nodes, and each node has a pool of transactions that need to be confirmed. Hence, mempool holds information for transactions that are yet to be confirmed. Nodes perform a number of checks to verify the validity of a transaction and send them to other nodes. Once a transaction is validated, and its validation is spread on the network, it is then selected by a mining node to be recorded in a block. Invalid transactions are removed from memory pools.