sentinel
/ˈsɛntɪn(ə)l
/noun
1A soldier or guard whose job is to stand and keep watch: soldiers stood sentinel with their muskets...
- Immediately, a sentinel standing guard near the jail confronted him.
- Men who have merited this last distinction are to be suffered to pass all guards and sentinels which officers are permitted to do.
- The sentinels who had stood watch throughout the night before watched those roadside dwellers with weary but alert eyes, should they suddenly decided to start a riot in front of the palace.
2 Medicine An indicator of the presence of disease: [as modifier]: the first national HIV sentinel surveillance programme in the developing world...
- We here present a model of field study, based on the use of sentinel species, that we are currently applying to risk assessment in the area around a focus of pollution.
- The beetles' affinity for certain trees, like maples, poplars, willows, and elms, is significant because such attractive species may be used as sentinel trees.
- Amphibians are regarded as sentinel vertebrates in the current drama of global extinctions.
verb (sentinels, sentinelling, sentinelled; US sentinels, sentineling, sentineled) [with object]
Station a soldier or guard by (a place) to keep watch: a wide course had been roped off and sentinelled with police
Origin
Late 16th century: from French sentinelle, from Italian sentinella, of unknown origin.