olemus
ajaloolises või sellest lähtuvas tähenduses

Wiktionary:
1.1. a broad piece of defensive armor, held in hand, formerly in general use in war, for the protection of the body
1.4. (mining, tunnelling) a framework used to protect workmen in making an adit under ground, and capable of being pushed along as excavation progresses
2.1. (heraldry) the field on which are placed the bearings in coats of arms.

näiteid
end shield -- otskilp
heat shield -- kuumakaitsekilp
human shield -- inimkilp
riot shield -- märulikilp
shield-shaped -- kilpjas
tax shield -- maksukilp (soodsa maksukliimaga riik)
tunneling shield -- läbinduskilp

ülevaateid
https://en.wikipedia.org/wiki/Shield

https://en.wikipedia.org/wiki/Riot_shield

https://en.wikipedia.org/wiki/Tunnelling_shield