presidential decree; presidential proclamation
Formal term for an official order or announcement issued by a president.
A new policy was implemented by presidential decree.
The presidential proclamation established a national holiday.
大統領令 is a more common term for 'executive order' in modern Japanese, while 大統領布告 is rarer and may carry a more formal or historical nuance.
Compound of 大統領 (president) and 布告 (proclamation, edict). The exact historical derivation is uncertain, but the term follows standard Sino-Japanese word formation.