special jury vs jury

special jury and jury both are nouns.

Word	Noun	Adjective	Verb	Adverb
special jury	Yes	No	No	No
jury	Yes	No	No	No

As nouns, jury is a hypernym of special jury; that is, jury is a word with a broader meaning than special jury:

special jury: a jury whose members are selected for special knowledge for a case involving complicated issues
jury: a body of citizens sworn to give a true verdict according to the evidence presented in a court of law

special jury (noun)	jury (noun)
a jury whose members are selected for special knowledge for a case involving complicated issues	a body of citizens sworn to give a true verdict according to the evidence presented in a court of law
	a committee appointed to judge a competition