Budget authority or the authorization of an appropriation in which all or some portion is available for a specified period in excess of one fiscal year. Multiple-year appropriations are identified within the Treasury Account Symbol using two digits separated by a slash (/) to indicate a multiple-year appropriation for incurring obligations for a definite period in excess of one fiscal year. The digit preceding the slash indicates the first fiscal year of availability, and the digit immediately following the slash indicates the final fiscal year of availability (020 18/19 1234).