shield vs protective covering

shield and protective covering both are nouns.

Word	Noun	Adjective	Verb	Adverb
shield	Yes	No	Yes	No
protective covering	Yes	No	No	No

As nouns, protective covering is a hypernym of shield; that is, protective covering is a word with a broader meaning than shield:

shield: a protective covering or structure
protective covering: a covering that is intend to protect from damage or injury

Other hypernyms of shield include protection, protective cover.

shield (noun)	protective covering (noun)
hard outer covering or case of certain organisms such as arthropods and turtles	the tough natural covering of some organisms
armor carried on the arm to intercept blows	a covering that is intend to protect from damage or injury
a protective covering or structure

shield (verb)	protective covering (verb)
protect, hide, or conceal from danger or harm
hold back a thought or feeling about