noun
sentinel
SEHN-tih-nuhl
noun
1
A person or animal that stands guard or keeps watch.
"A lone sentinel stood at the castle gate all night."
2
A sign that warns of a risk, such as an early symptom of a disease.
"Doctors treat the symptom as a sentinel for a more serious condition."
How to Use Sentinel
Learner’s notesIn plain EnglishSomeone or something that stands watch or gives early warning.
Common mistake
Sentinel and sentry overlap heavily; sentinel sounds slightly more formal or symbolic (a lone sentinel of the old order), while sentry is the everyday word for a guard on duty.
Easily confused with
Word Forms
sentineled past tense, sentinelled past tense, sentinels plural, sentinels singular
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A lone _____ stood at the castle gate all night.
Etymology
First recorded in the 1570s, from Middle French sentinelle, ultimately from Italian sentire, "to perceive or watch," from Latin sentiō, "to feel."