The term account is that it is a a record of debit and credit entries to indicate transactions involving a particular item or a particular person or concern. For the purposes of the Federal budget process, it has more specific definitions and in particular how it is used by the Government Accountability Office, which is the accounting oversight agency of the U.S. Congress.
Subaccount: The term subaccount means a record of financial transactions for groups of similar activities based on programs and subprograms. Each group has a unique number.
A separate financial reporting unit for budget, management, and/or accounting purposes. All budgetary transactions are recorded in accounts, but not all accounts are budgetary in nature. Some accounts do not directly affect the budget but are used purely for accounting purposes. Budget accounts are used to record all transfers within the budget, whereas other accounts (such as deposit fund, credit financing, and foreign currency accounts) are used for accounting purposes connected with funds that are nonbudgetary in nature. The Office of Management and Budget (OMB), in consultation with the Department of the Treasury (Treasury), assigns account identification codes reflecting appropriations as enacted in appropriations laws. Treasury establishes and maintains a system of accounts that provides the basic structure for the U.S. Standard General Ledger Chart of Accounts. (See also Accounts in the President’s Budget; Accounts for Purposes Other Than Budget Presentation; Credit Reform Act Accounts under Federal Credit; Standard General Ledger Chart of Accounts.)
The basic unit of an appropriation generally reflecting each unnumbered paragraph in an appropriation act. An appropriation account typically encompasses a number of activities or projects and may be subject to restrictions or conditions applicable to only the account, the appropriation act, titles within an appropriation act, other appropriation acts, or the government as a whole. (See also Appropriation Rider; Continuing Appropriation/ Continuing Resolution; Line Item; Supplemental Appropriation.)
Definition of Account from OMB Glossary
The following definition is found in the Analytical Perspectives volume of the President’s Budget. The “Glossary of Budget Terms” from that document carries definitions each year. Though updated each year, most definitions remain the same.
Account refers to a separate financial reporting unit used by the Federal Government to record budget authority, outlays and income for budgeting or management information purposes as well as for accounting purposes. All budget (and off-budget) accounts are classified as being either expenditure or receipt accounts and by fund group. Budget (and off-budget) transactions fall within either of two fund group: (1) Federal funds and (2) trust funds. (Cf. Federal funds group and trust funds group.)
Office of Management and Budget, Budget of the U.S. Government, Fiscal Year 2018: Analytical Perspectives (May 23, 2017), p. 88.