spore case vs sporangium

spore case and sporangium both are nouns.

Word	Noun	Adjective	Verb	Adverb
spore case	Yes	No	No	No
sporangium	Yes	No	No	No

As nouns, spore case and sporangium are synonyms defined as:

Other synonyms of spore case include spore sac.

spore case (noun)	sporangium (noun)
organ containing or producing spores	organ containing or producing spores
specialized leaf branch in certain aquatic ferns that encloses the sori or clusters of sporangia