A formal decree issued by an emperor, especially in historical contexts such as pre-war Japan.
Many imperial edicts were issued during the Meiji period.
詔書 refers to the written imperial edict itself, while 勅令 refers to an imperial ordinance having the force of law.
Compound of 勅 (imperial order) and 令 (decree, law). The exact historical derivation is straightforward from the kanji components.