decree nisi vs fiat

decree nisi and fiat both are nouns.

Word	Noun	Adjective	Verb	Adverb
decree nisi	Yes	No	No	No
fiat	Yes	No	No	No

As nouns, fiat is a hypernym of decree nisi; that is, fiat is a word with a broader meaning than decree nisi:

decree nisi: a decree issued on a first petition for divorce; becomes absolute at some later date
fiat: a legally binding command or decision entered on the court record (as if issued by a court or judge)

Other hypernyms of decree nisi include decree, edict, order, rescript.

decree nisi (noun)	fiat (noun)
a decree issued on a first petition for divorce; becomes absolute at some later date	a legally binding command or decision entered on the court record (as if issued by a court or judge)