Transaction (from English transaction - transaction) is, in a broad sense, a series of operations for the exchange of information, as a result of which changes are made to the system.
Most often this term is used in the performance of banking or exchange transactions, for example, when issuing cash from a card in a cash dispenser, when buying shares on the stock exchange or when calculating a card in a store. If the operation is "approved", then the transaction was successful, the money was written off and the buyer can pick up his goods with contented erysipelas. That is, here the transaction is an intentional transfer from your account of certain funds in favor of the seller. Each transaction is recorded in the bank's database, regardless of its success or failure (for example, if there is no money on the card).
In addition to finance, the term "transaction" is common in database programming. Here, the transaction is the sequence of changes made to the database. As with bank cards, a transaction can be approved (Commit) or canceled for some reason (Rollback), for example, if at some stage of the transaction the system tried to divide by zero or enter incorrect information into the database.
In psychology theory, and in particular, in psychoanalysis, a transaction is a communication unit between two people with a mandatory exchange of incentives.