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working dog

noun
  1. one of any of several breeds of usually large, powerful dogs originally developed to assist people in their daily work, as draft animals, guard dogs, and guide dogs, and including the boxer, bullmastiff, Doberman pinscher, Great Dane, St. Bernard, and Siberian Husky.

Origin of working dog

First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for working dog

working dog

noun
  1. a dog of suitable breed or training kept for its practical use, such as herding sheep, rather than as a pet or for showing
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012