from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A dog of a large powerful breed developed in England as a guard dog, having a large head, short black muzzle, and short often fawn-colored coat.

from The Century Dictionary.

  • noun A variety of dog of considerable antiquity.

from the GNU version of the Collaborative International Dictionary of English.

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

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun One of several large breeds of dog (such as bulldogs and Saint Bernards), often used as guard dogs

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English mastif, alteration (perhaps influenced by Old French mestif, mongrel) of Old French mastin, from Vulgar Latin *(canis) mānsuētīnus, tame (dog), from Latin mānsuētus, past participle of mānsuēscere, to tame : manus, hand; see man- in Indo-European roots + suēscere, to accustom; see s(w)e- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

An aberrant derivation from Old French mastin (modern French mâtin), from Vulgar Latin *mansuetīnus ("tamed (animal)"), from Latin mansuetus ("tamed").


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