Account classification definitions shape foreign reporting, excluded accounts, and entity status under the income-tax rules framework. Rule 238 provides the core definitions for rules 239 and 240, covering financial account, financial asset, financial institution, reportable account, reporting financial institution, reportable person, U.S. person, specified U.S. person, U.S. reportable account, relevant crypto-asset, U.S. source withholdable payment, withholding foreign partnership, and withholding foreign trust. It also defines excluded accounts, including retirement and pension accounts, certain insurance and savings arrangements, estate and transactional accounts, and low-value electronic-money accounts, together with institutional exemptions such as non-reporting financial institutions, exempt collective investment vehicles, local banks, sponsored entities, and qualified non-profit entities.