"special ordinance or regulation promulgated by authority," early 14c., originally ecclesiastical, secular use is by late 14c., from Old French decre, variant of decret (12c., Modern French décret), from Latin decretum, neuter of decretus, past participle of decernere "to decree, decide, pronounce a decision," from de (see de-) + cernere "to separate" (from PIE root *krei- "to sieve," thus "discriminate, distinguish").