mas ‧ tiff /ˈmæstəf, ˈmæstɪf/ BrE AmE ( also bull mastiff ) noun [countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: mastin , from Latin mansuetus 'easy to handle, not wild' ]
a large strong dog, often used to guard houses
mas ‧ tiff /ˈmæstəf, ˈmæstɪf/ BrE AmE ( also bull mastiff ) noun [countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: mastin , from Latin mansuetus 'easy to handle, not wild' ]
a large strong dog, often used to guard houses
Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012