sentinel: meaning, definition, pronunciation and examples
C1/C2Formal, Literary, Technical (computing/medicine)
Quick answer
What does “sentinel” mean?
A soldier or guard whose job is to stand and keep watch, often as a warning of danger.
Audio
Pronunciation
Definition
Meaning and Definition
A soldier or guard whose job is to stand and keep watch, often as a warning of danger.
A person or thing that watches or provides a warning; a protective indicator or device. In computing, a special value used to mark the end of a data structure.
Dialectal Variation
British vs American Usage
Differences
No significant difference in core meaning. 'Sentinel' is slightly more common in formal/literary British English (e.g., 'sentry' is more common for a physical guard). In American computing contexts, 'sentinel value' is standard.
Connotations
Both share connotations of vigilance, warning, and protection. Slightly more poetic/literary in both varieties.
Frequency
Low-frequency word in both dialects, with comparable usage levels.
Grammar
How to Use “sentinel” in a Sentence
[sentinel] + [over/for/of] + [object][serve/stand/act] + as + [a sentinel][sentinel] + [noun] (as modifier)Vocabulary
Collocations
Examples
Examples of “sentinel” in a Sentence
verb
British English
- The old fort still sentinels the harbour entrance.
- They sentinelled the perimeter throughout the night.
American English
- The mountain range sentinels the western border of the state.
- Special units were sentinelling the access points to the conference.
adverb
British English
- The tower stood sentinel-like over the valley.
- He watched sentinel, never moving from his post.
American English
- The statue remained sentinel, a silent witness to history.
- The program runs sentinel, checking for errors continuously.
adjective
British English
- The sentinel duty was assigned to the most experienced soldiers.
- A sentinel lymph node was identified for biopsy.
American English
- The sentinel guard reported movement in the woods.
- We implemented a sentinel event reporting system.
Usage
Meaning in Context
Business
Rare, except metaphorically in risk management (e.g., 'The algorithm acts as a sentinel for fraudulent transactions').
Academic
Used in history, literature, and computer science (e.g., 'Sentinel lymph node biopsy', 'sentinel loop in radiology').
Everyday
Very rare. Mostly in literary descriptions.
Technical
Common in computing (sentinel value/character), medicine (sentinel node/event), and environmental science (sentinel species).
Watch out
Common Mistakes When Using “sentinel”
- Misspelling as 'sentinle' or 'centinel'.
- Using it as a verb without the proper context ('He sentineled the gate' is non-standard; use 'He stood sentinel').
FAQ
Frequently Asked Questions
'Sentry' is more common for a physical, human guard posted at a specific point. 'Sentinel' is more formal/literary and is often used metaphorically for things that watch or warn.
Yes, but it is rare and considered literary or poetic (e.g., 'Towers sentinel the coast'). In everyday language, 'stand guard' or 'keep watch' is preferred.
It is a special value (like -1 or NULL) used to indicate the termination of a loop or the end of a data list, acting as a 'signal' to stop processing.
No, it is a low-frequency, C1/C2 level word. It is mostly found in formal writing, literature, and specific technical fields like medicine and computer science.
A soldier or guard whose job is to stand and keep watch, often as a warning of danger.
Sentinel is usually formal, literary, technical (computing/medicine) in register.
Sentinel: in British English it is pronounced /ˈsen.tɪ.nəl/, and in American English it is pronounced /ˈsen.tə.nəl/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “Stand sentinel over”
- “The silent sentinel”
Learning
Memory Aids
Mnemonic
Imagine a SENTry standing TALL and solENN (solemn) – a SENT-INN-EL guarding an inn.
Conceptual Metaphor
WATCHING IS GUARDING; A WARNING SYSTEM IS A SENTINEL.
Practice
Quiz
In which context is 'sentinel' most likely to be used literally?