mas·​tiff ˈma-stəf How to pronounce mastiff (audio)
: 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 English mastiff named Otis, traveling the world, and reconnecting. Wendy Grossman Kantor, Peoplemag, 12 May 2024 Murray, Milton, Robert and Lucas are four mastiffs − his dogs. Kim Hjelmgaard, USA TODAY, 10 May 2024 Kevin Hart: Chihuahua The combative, diminutive foil to his (mastiff) co-star. Rohita Kadambi, The New Yorker, 8 Feb. 2024 Duke, a 16-year-old pit bull and mastiff mix, died after receiving burns on roughly 70% of his body. Jose R. Gonzalez, The Arizona Republic, 14 Mar. 2024 Today there are more than 400 genetically distinct breeds, ranging from pint-size Pomeranians to massive mastiffs. Jack Tamisiea, Scientific American, 2 Feb. 2024 Peter Fisher, photographer and proud owner of a 2-year-old Boykin spaniel named Waylon Poodles and mastiffs and hounds, oh my! Bishop Sand, Washington Post, 6 Dec. 2023 Kathleen Morrill The results showed that Balto was only part Siberian husky, with additional ancestry relating to Alaskan sled dogs, village dogs, Greenland sled dogs, and Tibetan mastiffs. Jennifer Ouellette, Ars Technica, 27 Apr. 2023 Jessica introduced her Instagram followers to Lola, their Neapolitan mastiff puppy. Jacqueline Weiss, Peoplemag, 23 Oct. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'mastiff.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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

First Known Use

14th century, in the meaning defined above

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

Dictionary Entries Near mastiff

Cite this Entry

“Mastiff.” Dictionary, Merriam-Webster, Accessed 27 May. 2024.

Kids Definition


mas·​tiff ˈmas-təf How to pronounce mastiff (audio)
: any of a breed of large powerful smooth-coated dogs often used as watchdogs and guard dogs

More from Merriam-Webster on mastiff

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