A breed of large dogs noted for strength and courage. There are various strains, differing in form and color, and characteristic of different countries.

an old breed of powerful deep-chested smooth-coated dog used chiefly as a watchdog and guard dog

a giant breed of dog, descended from the ancient Alaunt and Molosser

Mastiff is a company that publishes video games, with offices located in both Tokyo and San Francisco. The exectuive staff includes Bill Swartz, Mika Hayashi, Ron Kurtz, and Charles Van.