cot vs sheath

cot and sheath both are nouns.

Word	Noun	Adjective	Verb	Adverb
cot	Yes	No	No	No
sheath	Yes	No	No	No

As nouns, sheath is a hypernym of cot; that is, sheath is a word with a broader meaning than cot:

cot (noun)	sheath (noun)
a small bed that folds up for storage or transport	a protective covering (as for a knife or sword)
baby bed with high sides made of slats	a dress suitable for formal occasions
a sheath worn to protect a finger	an enveloping structure or covering enclosing an animal or plant organ or part