pea pod vs seedcase

pea pod and seedcase both are nouns.

Word	Noun	Adjective	Verb	Adverb
pea pod	Yes	No	No	No
seedcase	Yes	No	No	No

As nouns, seedcase is a hypernym of pea pod; that is, seedcase is a word with a broader meaning than pea pod:

pea pod: husk of a pea; edible in some garden peas
seedcase: the vessel that contains the seeds of a plant (not the seeds themselves)

Other hypernyms of pea pod include cod, pod.

pea pod (noun)	seedcase (noun)
husk of a pea; edible in some garden peas	the vessel that contains the seeds of a plant (not the seeds themselves)