Boxer (dog) in the context of American Kennel Club

A mongrel, mutt, or mixed-breed dog is a dog that does not belong to one officially recognized breed, including those that result from intentional breeding. Although the term mixed-breed dog is sometimes preferred, many mongrels have no known purebred ancestors.

Crossbreed dogs, and "designer dogs", while also a mix of breeds, differ from mongrels in being intentionally bred. At other times, the word mongrel has been applied to informally purpose-bred dogs such as curs, which were created at least in part from mongrels, especially if the breed is not officially recognized.

A mongrel, mutt, or mixed-breed dog is any dog which does not belong to one officially recognized breed. While such terms may refer to all dogs of mixed breeds, the terms "dog crossbreed" and "designer dog" specifically refer to mixed-breed dogs which are intentionally bred.

Mixed-breed dogs may have ancestries that include any combination of purebred dogs and other mongrels.

Cropping is the removal of part or all of the external flaps of an animal's ear. The procedure sometimes involves bracing and taping the remainder of the ears to train them to point upright. Almost exclusively performed on dogs, it is an old practice that was once done for perceived health, practical or cosmetic reasons. Veterinary science states there is no medical or physical advantage to the animal from the procedure, leading to concerns of animal cruelty over performing unnecessary surgery on animals. In modern times, cropping is banned in many nations, but is still legal in a limited number of countries. Where permitted, it is seen only in certain breeds of dog, such as pit bull and bull terrier type breeds, the Doberman Pinscher, Schnauzer, Great Dane, Boxer and Cane Corso.