Section 136A. The following words as used in sections 137 to 174F, inclusive, shall have the following meanings unless the context requires otherwise:

''Adoption'', the delivery of a cat or dog to a person 18 years of age or older for the purpose of taking care of the dog or cat as a pet.

''Animal control officer'', an appointed officer authorized to enforce sections 136A to 174F, inclusive.

''Attack'', aggressive physical contact initiated by an animal.

''Commercial boarding or training kennel'', an establishment used for boarding, holding, day care, overnight stays or training of animals that are not the property of the owner of the establishment, at which such services are rendered in exchange for consideration and in the absence of the owner of any such animal; provided, however, that ''commercial boarding or training kennel'' shall not include an animal shelter or animal control facility, a pet shop licensed under section 39A of chapter 129, a grooming facility operated solely for the purpose of grooming and not for overnight boarding or an individual who temporarily, and not in the normal course of business, boards or cares for animals owned by others.

''Commercial breeder kennel'', an establishment, other than a personal kennel, engaged in the business of breeding animals for sale or exchange to wholesalers, brokers or pet shops in return for consideration.

''Commissioner'', the commissioner of agricultural resources.

''Dangerous dog'', a dog that either: (i) without justification, attacks a person or domestic animal causing physical injury or death; or (ii) behaves in a manner that a reasonable person would believe poses an unjustified imminent threat of physical injury or death to a person or to a domestic or owned animal.

''Department'', the department of agricultural resources.

''Domestic animal'', an animal designated as domestic by regulations promulgated by the department of fish and game.

''Domestic charitable corporation kennel'', a facility operated, owned or maintained by a domestic charitable corporation registered with the department or an animal welfare society or other nonprofit organization incorporated for the purpose of providing for and promoting the welfare, protection and humane treatment of animals, including a veterinary hospital or clinic operated by a licensed veterinarian, which operates consistent with such purposes while providing veterinary treatment and care.

''Euthanize'', to take the life of an animal by the administration of barbiturates in a manner deemed acceptable by the American Veterinary Medical Association Guidelines on Euthanasia.

''Hearing authority'', the selectmen of a town, mayor of a city, the officer in charge of the animal commission, the chief or commissioner of a police department, the chief or commissioner's designee or the person charged with the responsibility of handling dog complaints in a town or city.

''Keeper'', a person, business, corporation, entity or society, other than the owner, having possession of a dog.

''Kennel'', a pack or collection of dogs on a single premise, including a commercial boarding or training kennel, commercial breeder kennel, domestic charitable corporation kennel, personal kennel or veterinary kennel.

''License period'', the period of time for which a municipal licensing authority prescribes the validity of a dog license, including the date of issuance of the license through the date on which the license expires, inclusive.

''Licensing authority'', the police commissioner of the city of Boston and the clerk of any other municipality.

''Livestock or fowl'', a fowl or other animal kept or propagated by the owner for food or as a means of livelihood, deer, elk, cottontail rabbit, northern hare, pheasant, quail, partridge and other birds and quadrupeds determined by the department of fisheries, wildlife and environmental law enforcement to be wild and kept by, or under a permit from, the department in proper houses or suitable enclosed yards; provided, however, that ''livestock or fowl'' shall not include a dog, cat or other pet.

''Nuisance dog'', a dog that: (i) by excessive barking or other disturbance, is a source of annoyance to a sick person residing in the vicinity; or (ii) by excessive barking, causing damage or other interference, a reasonable person would find such behavior disruptive to one's quiet and peaceful enjoyment; or (iii) has threatened or attacked livestock, a domestic animal or a person, but such threat or attack was not a grossly disproportionate reaction under all the circumstances.

''Personal kennel'', a pack or collection of more than 4 dogs, 3 months old or older, owned or kept under single ownership, for private personal use; provided, however, that breeding of personally owned dogs may take place for the purpose of improving, exhibiting or showing the breed or for use in legal sporting activity or for other personal reasons; provided further, that selling, trading, bartering or distributing such breeding from a personal kennel shall be to other breeders or individuals by private sale only and not to wholesalers, brokers or pet shops; provided further, that a personal kennel shall not sell, trade, barter or distribute a dog not bred from its personally-owned dog; and provided further, that dogs temporarily housed at a personal kennel, in conjunction with an animal shelter or rescue registered with the department, may be sold, traded, bartered or distributed if the transfer is not for profit.

''Research institution'', an institution operated by the United States, the commonwealth or a political subdivision thereof, a school or college of medicine, public health, dentistry, pharmacy, veterinary medicine or agriculture, a medical diagnostic laboratory, a biomedical corporation, or biological laboratory or a hospital or other educational or scientific establishment within the commonwealth above the rank of secondary school which, in connection with any of the activities thereof, investigates or provides instruction relative to the structure or function of living organisms or to the cause, prevention, control or cure of diseases or abnormal conditions of human beings or animals.

''Shelter'', a public animal control facility or other facility which is operated by an organization or individual for the purpose of protecting animals from cruelty, neglect or abuse.

''Veterinary kennel'', a veterinary hospital or clinic that boards dogs for reasons in addition to medical treatment or care; provided, however, that ''veterinary kennel'' shall not include a hospital or clinic used solely to house dogs that have undergone veterinary treatment or observation or will do so only for the period of time necessary to accomplish that veterinary care.