mas·​tiff | \ˈmas-təf \

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

This was the second mastiff wolves had eaten on their property. Cori Petersen, WSJ, "Wolves Attack Wisconsin With Washington’s Help," 27 July 2018 Last year, animal rights groups protested after the Oregon Court of Appeals upheld a decision by a state judge requiring a couple to have their Tibetan mastiffs debarked. Lisa Gutierrez, kansascity, "Breeder 'debarked' dogs by shoving a pipe down their throats, Penn. authorities say," 30 May 2018 The short-nosed breeds include bulldogs, boxers, pugs, Boston terriers, Pekingese, mastiffs, shih tzus and others. Martine Powers, Washington Post, "More dogs die on United than on any other airline. Here’s why.," 4 Apr. 2018 One new and increasing potential danger are the farmers’ mastiff dogs, Smith explains. National Geographic, "Rare Bunny-Faced Mammal Captured on Video," 14 June 2018 As floats, bands, clowns, queens and even a bull mastiff march down the streets of Portland, drivers, buses, MAX trains and other modes of transportation get delayed. Rosemarie Stein,, "Traffic advisory: How to get around the 2018 Rose Festival Parade," 8 June 2018 Neighbors complained that the mastiff breeders' dogs barked incessantly. Lisa Gutierrez, kansascity, "Breeder 'debarked' dogs by shoving a pipe down their throats, Penn. authorities say," 30 May 2018 He is considered armed and dangerous and may be traveling with his mastiff-breed dog, a 160-pound Presa Canario, police said. Chelsea Prince, ajc, "Community rallies around teen daughter of woman found dead in Sandy Springs house fire," 29 May 2018 Back on the North Side, Fried and Sanchez stopped for an annual inspection at the home of Natalie McCallum, owner of a mastiff-boxer mix named Mugs, short for Mug Ruith, a powerful druid of Irish mythology. Vincent T. Davis, San Antonio Express-News, "Thousands of dog bites in S.A. include three-dozen cases against dangerous dogs," 26 May 2018

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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Last Updated

13 Nov 2018

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

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More Definitions for mastiff



English Language Learners Definition of mastiff

: a type of large, powerful dog


mas·​tiff | \ˈma-stəf \

Kids Definition of mastiff

: a very large powerful dog with a smooth coat

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More from Merriam-Webster on mastiff

Spanish Central: Translation of mastiff

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

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by force of circumstances

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