A validating mechanism for yet-to-be-verified transactions.
Mempool (short for memory pool) is a validating mechanism for nodes on a blockchain network. This mechanism is blockchain’s provisions for the waiting period between executing a transaction and said transaction being verified as completed on the network. Thus, while the trader waits for their transaction to be verified via the node-information broadcast process, the mempool takes note of the transaction.
The mempool function is one of the guards against mishaps such as double spending. Because the mechanism functions as a kind of memory cache, it is more difficult to carry out the same transaction twice.