Shield

noun

1. Anything that protects or defends; defense; shelter; protection.
2. A shape like that of a shield; usually, an inverted triangle with sides that curve inward to form a pointed bottom, commonly used for police identifications and company logos.
3. A large expanse of exposed stable Precambrian rock.
4. A place with a toilet seat: an outhouse; a lavatory.
5. Parts at the front and back of a vehicle which are meant to absorb the impact of a collision