What does sentinel mean?
A person or thing that watches or guards something, especially a person who is left to guard a place or a machine that automatically stops a process if something goes wrong. A biological marker or protein that is used to detect the presence of a disease or condition.
Example
"The security guard acted as a sentinel, watching the entrance to the building."
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.