Pet & veterinary glossary
47 plain-English definitions of the terms you\'ll hear at the vet, on your pet\'s medical records, or in any conversation about their care.
A
- Addison's disease Underproduction of cortisol and aldosterone by the adrenal glands. Sometimes called 'the great pretender' because signs are vague. Treatable but life-threatening at presentation.
- Anaesthesia Controlled unconsciousness used for surgery and many vet procedures (such as dental scaling) in pets. Modern protocols make it routinely safe even in older animals.
- Arthritis (osteoarthritis) Inflammation and degeneration of joint cartilage causing chronic pain and reduced mobility. The most common cause of pain in older dogs and cats — and widely under-diagnosed.
B
- Bloat (gastric dilatation-volvulus / GDV) A life-threatening emergency in deep-chested dogs where the stomach fills with gas and twists. Without surgery within hours, it is fatal.
- Body condition score (BCS) A 1–9 (or 1–5) scoring system vets use to assess whether a pet is the right weight. More useful than the scale because it accounts for build and muscle.
- Brachycephalic Having a flat or short muzzle. Breeds like Bulldogs, Pugs, French Bulldogs, Boxers, Cavaliers, Persians, and Exotic Shorthairs have specific health implications.
C
- Cancer in pets Uncontrolled cell growth. Common in older pets but increasingly treatable. Early detection meaningfully improves outcome for most types.
- Cat flu (feline upper respiratory infection) Common infection of cats caused by feline herpesvirus and/or calicivirus. Most adult cats recover; kittens and immunocompromised cats can be seriously ill.
- Chronic kidney disease (CKD) Progressive loss of kidney function. Affects around 75% of cats over 12 and a substantial share of senior dogs. Manageable when caught early.
- Cortisol A steroid hormone produced by the adrenal glands. Regulates stress response, metabolism, immune function, blood sugar. Too much causes Cushing's; too little, Addison's.
- Cruciate ligament rupture Tearing of the cranial cruciate ligament in the knee. The most common orthopaedic injury in dogs. Often surgical.
- Cushing's disease Overproduction of cortisol (the body's stress hormone), most commonly in older dogs. Causes increased thirst, urination, appetite, and a pot belly.
D
- Dental disease (periodontal disease) Inflammation of the tissues supporting the teeth, caused by plaque and tartar. Present in around 80% of dogs and 70% of cats by age 3. Painful and shortens lifespan.
- Dental scaling Professional cleaning of teeth under anaesthesia using ultrasonic and hand instruments to remove plaque and tartar above and below the gum line.
- Diabetes mellitus Insufficient insulin or insulin resistance leading to high blood sugar. Common in older overweight cats and middle-aged dogs. Highly manageable with twice-daily insulin.
E
F
- Fleas Tiny blood-feeding insects that cause itching and skin disease. The most common parasite of pets. Most pets are not "scratching" — they are flea-allergic.
- FLUTD (feline lower urinary tract disease) Umbrella term for problems affecting the bladder and urethra in cats. Most common cause: idiopathic cystitis. Male urethral obstruction is a true emergency.
- Food allergy / intolerance An adverse reaction to a food component, most often a protein. Causes skin or gut signs. Diagnosed by 8–12 week elimination diet.
G
H
- Heart disease (dogs) Most often degenerative valve disease in small breeds or dilated cardiomyopathy in large breeds. Progressive, manageable, eventually causes congestive heart failure.
- Heartworm A parasitic worm that lives in the heart and major blood vessels of dogs (and rarely cats), transmitted by mosquitos. Preventable. Treatment is risky and expensive.
- Hip dysplasia Abnormal development of the hip joint where the ball and socket don't fit properly. Inherited; common in many large breeds. Leads to arthritis.
- Hyperthyroidism Overactive thyroid gland producing too much thyroid hormone. The most common endocrine disease in older cats. Highly treatable.
- Hypertrophic cardiomyopathy (HCM) The most common heart disease in cats — thickening of the heart muscle. Often silent until decompensation. Maine Coons, Ragdolls, British Shorthairs predisposed.
I
K
L
M
- Mast cell tumour A common skin tumour in dogs that can range from a benign lump to an aggressive cancer. Many present as a "boring" skin bump and need biopsy.
- Microchip A rice-grain-sized RFID chip injected under the skin between the shoulder blades. Holds a unique ID number linking to the owner's contact details in a national registry.
N
- Neutering / de-sexing / spaying / castration Surgical removal of the reproductive organs. Spaying = female (ovaries and usually uterus); castration / neutering = male (testicles). Population control + health benefits.
- Noise phobia Extreme fear of specific sounds — fireworks, thunder, gunshots. Common, treatable, and often progressive if ignored.
- NSAID (non-steroidal anti-inflammatory drug) Anti-inflammatory and pain medication used widely for arthritis and post-surgical pain. Vet-prescribed pet NSAIDs are very different from human ones and human versions are dangerous.
O
P
- Pancreas Small organ near the stomach producing digestive enzymes (exocrine) and insulin (endocrine). Source of two important conditions: pancreatitis and diabetes.
- Pancreatitis Inflammation of the pancreas. Often triggered by a high-fat meal in dogs; subtler in cats. Can range from mild and self-limiting to severe and life-threatening.
- Paralysis tick (Ixodes holocyclus) An Australian tick whose toxin causes progressive paralysis in pets. Without rapid vet treatment, often fatal. Preventable.
- Parasite prevention Routine medications protecting pets against fleas, ticks, heartworm, and intestinal worms. Year-round, vet-recommended schedule.
- Parvovirus (parvo) A highly contagious, often fatal viral disease of puppies. Causes severe bloody diarrhoea and vomiting. Preventable by vaccination.
- Pet insurance Insurance that reimburses a portion of veterinary costs for accidents, illness, or both. Most valuable when purchased before any pre-existing condition develops.
- Pyometra A life-threatening uterine infection in entire (un-de-sexed) older female dogs and cats. Surgical emergency. Eliminated by spaying.