stadium vs sports stadium

stadium and sports stadium both are nouns.

Word	Noun	Adjective	Verb	Adverb
stadium	Yes	No	No	No
sports stadium	Yes	No	No	No

As nouns, stadium and sports stadium are synonyms defined as:

stadium and sports stadium: a large structure for open-air sports or entertainments

Other synonyms of stadium include arena, bowl.

stadium (noun)	sports stadium (noun)
a large structure for open-air sports or entertainments	a large structure for open-air sports or entertainments