The U.S. government has a number of appropriations accounts to keep appropriations activities organized.
Government Accountability Office Definition
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.)