Learn in the textbookThe Foundations of Electronic Payment and Data Exchange
DefinitionAccount aggregation (アカウントアグリゲーション) is a service that gathers a user's account information from several financial institutions into one app or screen so it can all be checked together.
ExplanationA household budgeting app, for example, shows bank balances, holdings at a brokerage and card statements side by side on one screen. Users can see the whole picture of their money without logging in to each institution separately.
AnalogyIt is like an agent who collects the statements arriving in mailboxes all over town and delivers them to you in a single box each day.
Memory hook"Aggregate" means to gather together and "account" is a bank account; the one who looks at the gathered account information is the user, to see the whole picture of their own money.