certiorari vs judicial writ

certiorari and judicial writ both are nouns.

Word	Noun	Adjective	Verb	Adverb
certiorari	Yes	No	No	No
judicial writ	Yes	No	No	No

As nouns, judicial writ is a hypernym of certiorari; that is, judicial writ is a word with a broader meaning than certiorari:

certiorari: a common law writ issued by a superior court to one of inferior jurisdiction demanding the record of a particular case
judicial writ: (law) a legal document issued by a court or judicial officer

Other hypernyms of certiorari include writ.

certiorari (noun)	judicial writ (noun)
a common law writ issued by a superior court to one of inferior jurisdiction demanding the record of a particular case	(law) a legal document issued by a court or judicial officer