This is an accounting year, i.e. when the books for the year are opened and closed. It can coorespond to the calander year or be say, July 1 to June 30, as many governments have it.
The accounting period for which annual financial statements are regularly prepared, generally a period of 12 months, 52 weeks, or 53 weeks.
Financial operations of the federal government are carried out in a 12-month fiscal year, beginning on Oct. 1 and ending on Sept. 30. The fiscal year carries the date of the calendar year in which it ends. (From fiscal year 1844 to fiscal year 1976, the fiscal year began July 1 and ended the following June 30.)