groundnut vs tuber

groundnut and tuber both are nouns.

Word	Noun	Adjective	Verb	Adverb
groundnut	Yes	No	No	No
tuber	Yes	No	No	No

As nouns, tuber is a hypernym of groundnut; that is, tuber is a word with a broader meaning than groundnut:

groundnut: nutlike tuber; important food of Native Americans
tuber: a fleshy underground stem or root serving for reproductive and food storage

groundnut (noun)	tuber (noun)
nutlike tuber; important food of Native Americans	a fleshy underground stem or root serving for reproductive and food storage
pod of the peanut vine containing usually 2 nuts or seeds; `groundnut' and `monkey nut' are British terms
a North American vine with fragrant blossoms and edible tubers; important food crop of Native Americans