mastiff

noun

mas·​tiff ˈma-stəf 

: 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

Examples of mastiff in a Sentence

Recent Examples on the Web

After the tragedy, Gibson's attorney said the actor had since rehomed his beloved mastiffs. —Nicholas Rice, PEOPLE, 4 Oct. 2025

Located in the elegant Evasion Mont Blanc, there are nearly 250 miles of slopes spread over four mastiffs to ski here, and well, to plot. —Kathleen Rellihan, Outside, 5 Sep. 2025

Cane Corsos, an ancient Italian mastiff breed, are renowned for their sheer size and protective instincts. —Melissa Fleur Afshar, MSNBC Newsweek, 2 Sep. 2025

The Guinness World Record for most puppies in one litter belongs to Tia, a Neapolitan mastiff who gave birth to 24 puppies on Nov. 29, 2004, in Manea, U.K. —Kimberlee Speakman, People.com, 2 Sep. 2025

Word History

Etymology

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

Kids Definition

mastiff

noun

mas·​tiff ˈmas-təf 

: any of a breed of large powerful smooth-coated dogs often used as watchdogs and guard dogs