Mastiff

n.

1.

(Zool.) A breed of large dogs noted for strength and courage. There are various strains, differing in form and color, and characteristic of different countries. Mastiff bat (Zool.) , any bat of the genus Molossus; so called because the face somewhat resembles that of a mastiff.

Noun

1.

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

Tibetan mastiff, working dog