sen·​ti·​nel | \ ˈsent-nəl How to pronounce sentinel (audio) , ˈsen-tə-nəl \

Definition of sentinel

 (Entry 1 of 2)

: sentry


sentineled or sentinelled; sentineling or sentinelling

Definition of sentinel (Entry 2 of 2)

transitive verb

1 : to watch over as a sentinel
2 : to furnish with a sentinel
3 : to post as sentinel

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Examples of sentinel in a Sentence

Noun a lone sentinel kept watch over the fort
Recent Examples on the Web: Noun Now, because of Covid-19, shoppers enter mainly by appointment, making Mr. Teran a combination bouncer, receptionist, health-care worker and sentinel. Renata Geraldo, WSJ, "He Used to Guard the Door. Now He Takes Names and Temperatures, Too.," 25 Nov. 2020 Casey Schoenebeck, a research scientist who runs the DNR's sentinel lakes program, said Olmanson's heat map is supported by what his team has found in the water. Jennifer Bjorhus, Star Tribune, "North-central Minnesota lakes are getting murkier faster," 20 Feb. 2021 One such sentinel is the cancer-suppressor gene TP53. Athena Aktipis, Scientific American, "How Evolution Helps Us Understand Cancer and Control It," 1 Jan. 2021 The city’s Christmas tree, missing branches and all, stands sentinel over a park that is missing a few things too. Steve Rubenstein,, "Merry Christmas? S.F.’s subdued tree-lighting ‘par for the course for 2020’," 11 Dec. 2020 The Court is back as a sentinel protecting the free exercise of religion, even in a health emergency. The Editorial Board, WSJ, "Fireworks Over Religious Liberty," 26 Nov. 2020 Another piece of San Francisco’s history will soon disappear: The glowing Coca-Cola sign that has stood sentinel for Bay Bridge commuters for nearly a century is coming down. Vanessa Arredondo,, "‘Please don’t tear it down’: San Francisco losing its 83-year-old Coca-Cola billboard," 26 Oct. 2020 The chancellor said of the 433 sentinel tests of a random campus sampling done in Tuscaloosa so far this week, three came back positive. Michael Casagrande |, al, "University of Alabama reports second straight drop in weekly COVID-19 positives," 18 Sep. 2020 In the sameness that life often breeds, Mabel stood as a sentinel to change, a bundle of unpredictability. Steve Straessle, Arkansas Online, "OPINION | STEVE STRAESSLE: Not quite right," 5 Sep. 2020 Recent Examples on the Web: Verb Expanding Centers for Disease Control and Prevention sentinel surveillance programs and other surveillance programs to offer tests not only to those who ask but also to those who may not know to ask is also on Biden's Plan to Combat Coronavirus. USA Today, "Comparing Trump and Biden's plans to end the COVID-19 pandemic," 2 Nov. 2020 And there are certain types of events or sentinel events that require a deeper dive before continuing to ensure the safety of current and future participants. Adrian Hernandez, STAT, "Covid-19 clinical trial pauses ‘show the system is working’," 14 Oct. 2020 Auburn continues to rely on self-reporting and sentinel testing to keep track of its numbers. Giana Han, al, "Auburn University reports second drop in positive COVID-19 cases," 22 Sep. 2020 It has been guarded every hour of every day since 1937 by elite Tomb Guard sentinels. Jesse Ryan, USA TODAY, "VR: Witness a sacred ritual and America’s highest honor at Arlington National Cemetery," 29 May 2017 When Chinese leaders gaze out toward the Pacific, their panorama is obstructed by a string of military airfields, naval anchorages, radar emplacements and listening posts sentineled by U.S. forces and their allies. Andrew Browne, WSJ, "To China, America Finally Looks Vulnerable," 14 Mar. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sentinel.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of sentinel


1579, in the meaning defined above


1593, in the meaning defined at sense 1

History and Etymology for sentinel


Middle French sentinelle, from Old Italian sentinella, from sentina vigilance, from sentire to perceive, from Latin

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Learn More about sentinel

Time Traveler for sentinel

Time Traveler

The first known use of sentinel was in 1579

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Statistics for sentinel

Last Updated

20 Mar 2021

Cite this Entry

“Sentinel.” Dictionary, Merriam-Webster, Accessed 16 Apr. 2021.

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More Definitions for sentinel


sen·​ti·​nel | \ ˈsen-tə-nəl How to pronounce sentinel (audio) \

Kids Definition of sentinel

: sentry


sen·​ti·​nel | \ ˈsent-ᵊn-əl How to pronounce sentinel (audio) \

Medical Definition of sentinel

: being an individual or part of a population potentially susceptible to an infection or infestation that is being monitored for the appearance or recurrence of the causative pathogen or parasite

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