mas·​tiff | \ ˈma-stəf How to pronounce mastiff (audio) \

Definition of mastiff

: any of a breed of very large massive powerful smooth-coated dogs that are apricot, fawn, or brindle and are often used as guard dogs

Illustration of mastiff

Illustration of mastiff

Examples of mastiff in a Sentence

Recent Examples on the Web Gina and her husband did it with their second dog, Charlie, a pit bull/mastiff/hound mix who knew how to sit and was good on a leash but was painfully shy. John Kelly, Washington Post, "This website lets rescue dog adopters connect with the pet’s previous owners," 18 Oct. 2020 Lacey is adjusting well to her new home and older canine sister, Remi, a 9-month-old English mastiff. Sydney Page Washington Post, Star Tribune, "A boy with a cleft lip meets a puppy with a cleft lip and 'they instantly loved each other'," 9 Oct. 2020 The mastiff was so weak that Benjamin had to lift it into his squad car. Shannon Prather, Star Tribune, "Animal aid groups help give local dogs a new lease on life," 20 Aug. 2020 And not even another large breed such as a Great Pyrenees or a mastiff or an Irish wolfhound. Arkansas Online, "EDITORIAL: It's the pits, all right," 8 Aug. 2020 Their home is guarded by two mastiffs, and jaguars and tigers frequently roam around their eight-acre yard. Washington Post, "Get our Coronavirus Updates newsletter," 9 May 2020 On Sunday, Detroit Pit Crew Dog Rescue, which doctored Penelope back to health, announced on its Facebook page that English mastiff has been adopted by an Eastpointe police sergeant and his family. Christina Hall, Detroit Free Press, "New Eastpointe law cracks down on when dogs can be left outside," 3 Feb. 2020 Tibetan people have used mastiffs guard their flocks of sheep from predators, like wolves, for centuries. Jason Daley, Smithsonian, "Wolves Gave Tibetan Mastiffs Their Mountaineering Genes," 9 Sep. 2019 Now, the approximately 3-year-old English mastiff weighs 136 pounds. Christina Hall, Detroit Free Press, "New Eastpointe law cracks down on when dogs can be left outside," 3 Feb. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mastiff.' 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 mastiff

14th century, in the meaning defined above

History and Etymology for mastiff

Middle English mastif, from Medieval Latin mastivus, from Vulgar Latin *masuetivus, from Latin mansuetus tame — more at mansuetude

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Time Traveler for mastiff

Time Traveler

The first known use of mastiff was in the 14th century

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Last Updated

27 Oct 2020

Cite this Entry

“Mastiff.” Dictionary, Merriam-Webster, Accessed 28 Oct. 2020.

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More Definitions for mastiff


How to pronounce mastiff (audio)

English Language Learners Definition of mastiff

: a type of large, powerful dog


mas·​tiff | \ ˈma-stəf How to pronounce mastiff (audio) \

Kids Definition of mastiff

: a very large powerful dog with a smooth coat

More from Merriam-Webster on mastiff

Nglish: Translation of mastiff for Spanish Speakers Encyclopedia article about mastiff

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