shell vs armor plating

shell and armor plating both are nouns.

Word	Noun	Adjective	Verb	Adverb
shell	Yes	No	Yes	No
armor plating	Yes	No	No	No

As nouns, armor plating is a hyponym of shell; that is, armor plating is a word with a more specific, narrower meaning than shell:

shell: a metal sheathing of uniform thickness (such as the shield attached to an artillery piece to protect the gunners)
armor plating: specially hardened steel plate used to protect fortifications or vehicles from enemy fire

Other hyponyms of shell include armor plate, armour plate, plate armor, plate armour, horseshoe, shoe, shell plating.

shell (noun)	armor plating (noun)
the hard largely calcareous covering of a mollusc or a brachiopod	specially hardened steel plate used to protect fortifications or vehicles from enemy fire
hard outer covering or case of certain organisms such as arthropods and turtles
ammunition consisting of a cylindrical metal casing containing an explosive charge and a projectile; fired from a large gun
a metal sheathing of uniform thickness (such as the shield attached to an artillery piece to protect the gunners)
the housing or outer covering of something
a very light narrow racing boat
a rigid covering that envelops an object
the exterior covering of a bird's egg
the hard usually fibrous outer layer of some fruits especially nuts
the material that forms the hard outer covering of many animals

shell (verb)	armor plating (verb)
remove from its shell or outer covering
remove the husks from
use explosives on
come out better in a competition, race, or conflict
hit the pitches of hard and regularly
look for and collect shells by the seashore
fall out of the pod or husk
create by using explosives