protection vs sheath

protection and sheath both are nouns.

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

As nouns, sheath is a hyponym of protection; that is, sheath is a word with a more specific, narrower meaning than protection:

protection (noun)	sheath (noun)
the activity of protecting someone or something	a protective covering (as for a knife or sword)
payment extorted by gangsters on threat of violence	a dress suitable for formal occasions
kindly endorsement and guidance	an enveloping structure or covering enclosing an animal or plant organ or part
the imposition of duties or quotas on imports in order to protect domestic industry against foreign competition
a covering that is intend to protect from damage or injury
defense against financial failure; financial independence
the condition of being protected