shield
CEFR: B2
A protective mechanical cylindrical barrier used in subterranean tunneling (tunnel boring shield); or to protect from harm.
Synonyms
- tunnelling shield
- barrier
- safeguard
Common Collocations
- shield from radiation
- human shield
- protective shield
Example Sentence
The invention of the Greathead shield enabled engineers to bore deep tube tunnels through soft London clay without surface collapses.