[noun] [C] [esp. old use or literary] - a person employed to guard something; a sentryAt every gate that we passed through, we saw a watchman - on every bridge a sentinel.A policeman stood sentinel at the entrance.(esp. US) Sentinel is also used in the names of some newspapers.the Fort Lauderdale Sun-Sentinelthe Fitchburg Sentinel
SENTINEL
Meaning of SENTINEL in English
Cambridge English vocab. Кембриджский английский словарь. 2012