Transaction
agreement, or communication, carried out between a buyer and a seller to exchange an asset for payment / From Wikipedia, the free encyclopedia
A transaction is usually an exchange. Sometimes other things are referred to as transactions.
A business transaction is one where money, goods, or services are bought, sold or traded.
A bank transaction is when money is taken out of, put into, or moved around inside of a bank.
A database transaction is one where data is changed inside a computer system.