Glossary

225 terms defined in plain English. Each one links to the latest coverage in the index, and to the tools and guides that use it.

A

Adopting a FIV-positive cat: Taking home a cat that tests positive for feline immunodeficiency virus, which many live with for years given good care.

Adoption fee: The payment a shelter or rescue asks when you adopt a cat, which usually helps cover its veterinary care and the cost of running the organisation.

Adult cat: A fully grown cat, roughly from two to six years old, in its prime and needing steady care, exercise and a weight-controlled diet.

Allogrooming: One cat licking another, usually around the head and neck, which strengthens bonds between cats that live together.

Anemia: A shortage of red blood cells or hemoglobin, which leaves a cat weak and pale and always has an underlying cause.

Anesthesia: The medically controlled loss of consciousness and pain sensation that lets a vet perform surgery, dental work or imaging safely.

Animal shelter: A facility that takes in stray, lost and surrendered animals, holds them, and works to return them to owners or place them in new homes.

Apex predator: An animal at the top of its food chain that adults of the species hunt and that has no natural predators of its own.

Arachidonic acid: An omega-6 fatty acid that cats cannot make from plant oils in sufficient amounts and so need ready-made from animal fat.

Arterial thromboembolism: A blood clot that lodges in an artery, most often cutting off blood to a cat's back legs and causing sudden pain and paralysis.

Automatic feeder: A device that releases set portions of cat food at programmed times, or only for a cat it recognises by its microchip or tag.

Avian influenza: A bird virus, in recent years H5N1, that can infect cats through raw milk, raw pet food or wild birds and make them seriously ill.

B

Barn cat: A neutered, usually unsocialised cat placed in a barn, stable or yard with food and shelter, where it helps control rodents.

Bicolour cat: A cat whose coat combines white with one other colour, in patches of varying size, from a few spots to mostly white.

Big cat: An informal name for the largest wild cats, usually the lion, tiger, leopard and jaguar, and often the snow leopard, cheetah and cougar too.

Big cat sanctuary: A facility that gives lifetime care to captive big cats without breeding them, trading them or allowing public contact, unlike a roadside zoo.

Black panther: A popular name for a black leopard in Asia and Africa or a black jaguar in the Americas; there is no species of that name.

Bladder crystals: Microscopic mineral particles in urine that can clump into stones and irritate or block a cat's urinary tract.

Blood panel: A set of blood tests that counts cells and measures chemicals to show how a cat's organs are working.

Blood pressure: The force of blood against artery walls; high readings in cats usually come from another disease and can damage the eyes, brain, heart and kidneys.

Bobtail: A cat with a naturally short, stubby or kinked tail, a trait that occurs in several breeds and mixed-breed populations.

Body condition score: A hands-on rating of how lean or fat a cat is, on a scale such as 1 to 9, used by vets because weight alone can mislead.

Body language: How a cat shows mood and intent through its tail, ears, eyes, whiskers, posture and fur.

Bonded pair: Two cats with a close attachment to each other, often adopted together by shelters and rescues so they are not separated.

Brachycephalic: Having a short, broad skull and flattened face, as in Persians and Exotic Shorthairs, which often brings breathing, eye and dental problems.

Breakaway collar: A cat collar with a clasp designed to pop open under strain so the cat can free itself if the collar snags.

Breed standard: The written description of the ideal cat of a breed, covering head, body, coat, colour and temperament, used by judges and breeders.

Britches: The long, full fur on the backs of a longhaired cat's hind legs, which forms a pair of fluffy trousers.

Bunting: A cat pressing its head, cheeks or chin against a person, object or another cat to leave scent and say hello.

C

Calico: A cat with large patches of white, black and orange, a coat pattern that occurs almost only in females.

Camera trap: A motion-triggered camera left in the field that photographs passing animals, widely used to count shy wild cats such as tigers and jaguars.

Captive breeding: Breeding a threatened species under human care, in zoos or breeding centres, to keep a safe population and sometimes supply animals for release.

Carnassial teeth: The large cheek teeth, a cat's upper fourth premolar and lower first molar, that slide past each other like scissors to slice meat.

Cat bite abscess: A pocket of pus under the skin that forms after a bite or scratch from another cat, common in outdoor, unneutered males.

Cat carrier: A secure, ventilated box or bag for moving a cat safely to the vet, on a trip or in an emergency.

Cat harness: A set of straps or a vest that fits around a cat's chest and back so it can be clipped to a lead for supervised outdoor time.

Cat registry: An organisation that records cats' ancestry, issues pedigree certificates, defines breed standards and licenses cat shows.

Cat scratch disease: A bacterial infection people can get from a cat's scratch or bite, carried by cats that usually look healthy.

Cat show: An event where cats are judged against the written standard for their breed or, in a household pet class, on condition and temperament.

Cat tree: A multi-level piece of furniture with platforms, perches, hideaways and scratching surfaces that lets an indoor cat climb and survey the room.

Cat water fountain: A small pump-driven bowl that keeps drinking water moving and filtered, which some cats find more appealing than a still bowl.

Cat-proofing: Checking a home for hazards a curious cat could chew, swallow, climb, squeeze into or fall from, and removing or blocking them.

Catio: A fully enclosed outdoor space, from a window box to a garden room, where a cat can enjoy fresh air without roaming free.

Catnip: A mint-family herb whose scent triggers a short burst of playful or mellow behaviour in about two out of three cats.

Cattery: A place where cats are bred, or where they are boarded while their owners are away, depending on the country and context.

CFA: The Cat Fanciers' Association, a United States-based registry of pedigree cats founded in 1906 that sets breed standards and runs cat shows.

Chattering: The rapid clicking of the jaw and teeth, often with chirps, that cats make when watching prey they cannot reach.

Chronic kidney disease: A gradual loss of kidney function, common in older cats, that can be managed for months or years but not cured.

Clicker training: A training method that marks the exact moment a cat does the right thing with a click, followed by a treat.

Clumping litter: Cat litter that binds urine into firm lumps you can scoop out, leaving the rest of the box clean and reusable.

Colony caretaker: A person who feeds and watches over an outdoor cat colony, and usually arranges neutering, vaccination and veterinary help for its cats.

Colourpoint: A coat pattern with a pale body and darker ears, face, legs and tail, caused by a temperature-sensitive pigment gene.

Community cat: An umbrella term for any cat living outdoors that is not confined, whether friendly or feral, owned or unowned.

Complete and balanced: A pet-food label claim that a food supplies all the nutrients a cat needs at a stated life stage, when used as the only diet.

Core vaccines: The vaccines vets recommend for every cat, as opposed to non-core vaccines chosen according to a cat's lifestyle and risk.

Crepuscular: Most active at dawn and dusk, the pattern cats follow because their natural prey is busiest at those times.

Cryptorchid: A male cat with one or both testicles that have not moved down into the scrotum, staying in the groin or abdomen.

Cystitis: Inflammation of the bladder, which in cats is often stress-linked and has no infection or stone behind it.

D

Declawing: A surgery that amputates the last bone of each toe, not just the claw, and is banned or discouraged in many places.

Dehydration: A shortage of body water that can accompany vomiting, diarrhea, kidney disease and many other illnesses in cats.

Dewclaw: The small thumb-like claw higher up on the inner side of each front leg that does not touch the ground.

Diabetes mellitus: A disease in which a cat's body cannot make or use insulin properly, so blood sugar stays too high.

Domestic longhair: A long-coated cat of mixed or unknown ancestry rather than a recognised breed, such as a fluffy shelter or household cat.

Domestic shorthair: The everyday short-coated cat of no particular breed, the most common type of pet cat in the world and in shelters.

Double coat: A coat made of a soft insulating undercoat beneath longer, coarser guard hairs, found in many cold-climate and semi-longhair breeds.

Dry food: Cat food baked or extruded into small pieces with about 10 percent water, convenient and shelf-stable but low in moisture.

E

Ear mites: Tiny surface parasites that live in a cat's ear canal and cause itching and dark, crumbly debris.

Ear-tipping: The removal of the tip of one ear under anaesthesia, done at neutering, to show at a glance that a free-roaming cat has been sterilised.

Endangered species: A species at high risk of extinction, either under the IUCN Endangered category or on a legal list that protects it, which are different systems.

Enrichment: Giving a cat chances to carry out natural behaviours such as climbing, hunting, scratching, hiding and exploring, so it stays well and busy.

Euthanasia: A veterinarian's painless medical procedure to end an animal's life peacefully when suffering cannot be relieved.

F

Felid: Any member of the cat family, Felidae, from the house cat to the tiger, and including extinct cats such as the sabre-toothed cats.

Feline acne: A skin condition that shows as blackheads and sometimes sores on a cat's chin and lower lip.

Feline asthma: A long-term inflammation of a cat's small airways that causes coughing, wheezing and sometimes sudden breathing difficulty.

Feline calicivirus: A common virus behind cat flu that causes sneezing, eye discharge and painful mouth ulcers, and sometimes severe illness.

Feline herpesvirus: A common virus that causes sneezing, eye inflammation and nasal discharge, and stays in the body for life, flaring up in times of stress.

Feline immunodeficiency virus: A slow-acting virus, spread mainly by deep bite wounds, that gradually weakens a cat's immune defences.

Feline infectious peritonitis: A serious disease caused when a common, usually harmless feline coronavirus mutates and triggers widespread inflammation in the body.

Feline leukemia virus: A contagious virus that weakens a cat's immune system and can cause anemia, infections and cancer such as lymphoma.

Feline panleukopenia: A highly contagious and often deadly parvovirus that attacks fast-dividing cells, mainly in unvaccinated kittens.

Feral cat: A cat that has not been socialised to people and lives outdoors, avoiding contact and usually not suited to life as a house pet.

FIFe: The Fédération Internationale Féline, an umbrella body of national cat clubs, mainly in Europe, founded in 1949, that sets shared breed rules.

Filial generation: A count of generations since a wild-cat ancestor, with F1 the first cross, used for hybrid breeds such as the Bengal and Savannah.

Flea: A tiny blood-feeding insect that lives on cats, causes itching and allergy, and carries tapeworm and other infections.

Flea allergy dermatitis: An itchy skin disease caused by an allergic reaction to flea saliva, where even a few bites trigger scabs and hair loss.

Flehmen response: The open-mouthed grimace a cat makes when it draws a scent to a special organ in the roof of its mouth.

FLUTD: An umbrella term for the conditions that cause pain, straining and bloody urine in a cat's bladder and urethra.

Folded ears: Ears that bend forward and down because of a gene that also affects cartilage throughout the body, as in the Scottish Fold.

Foster care: Caring for a shelter or rescue cat in your own home for a limited time until it is adopted, often a kitten, a mother or a recovering cat.

Foster-to-adopt: An arrangement in which you take a shelter or rescue cat home for a trial period before deciding to adopt it permanently.

Free feeding: Leaving food out all day so a cat can eat when it likes, which suits some cats but often leads to overeating.

FVRCP vaccine: The combination cat vaccine that protects against feline herpesvirus, calicivirus and panleukopenia.

G

GCCF: The Governing Council of the Cat Fancy, the main registry for pedigree cats in the United Kingdom, formed in 1910 from several cat clubs.

Geriatric cat: A cat aged about 15 or older, who needs closer monitoring, a comfortable home and a focus on quality of life.

Grain-free: Cat food made without wheat, corn, rice and other grains, which does not make it low in carbohydrate or better for most cats.

Guard hairs: The long, coarse outer hairs of a cat's coat that shed water and dirt and carry its colour and pattern.

H

Hairball: A wet clump of swallowed fur that a cat brings up, normal now and then but worth a vet visit if frequent.

Hairball formula: A cat food with extra fibre meant to move swallowed hair through the gut, which may help some cats, alongside brushing.

Hairless cat: A cat bred for a coat that is absent or very short and fine, so the skin shows; the Sphynx is the best-known example.

Heartworm: A parasite spread by mosquitoes that lives in the lungs and heart vessels and can cause breathing problems, vomiting or sudden collapse in cats.

Hepatic lipidosis: A serious liver disease in which fat builds up in liver cells after a cat stops eating, most often in overweight cats.

Hissing: A sharp, breathy warning sound a frightened or angry cat makes to tell another animal or person to back off.

Hookworm: A small intestinal worm that attaches to the gut wall and feeds on blood, causing anemia, especially in kittens.

Hospice care: Care for a cat with an incurable illness that focuses on comfort, pain relief and quality of life rather than cure.

Human-wildlife conflict: Harm that people and wild animals cause each other, such as big cats killing livestock and herders killing cats in return.

Hybrid cat: A cat bred from a domestic cat and a wild species, such as the Bengal from the Asian leopard cat or the Savannah from the serval.

Hydration: Keeping a cat's body supplied with enough water, which matters because cats drink little and are prone to urinary and kidney problems.

Hyoid apparatus: The chain of small bones and ligaments supporting the tongue and larynx, whose structure helps explain why some cats roar and others purr.

Hyperthyroidism: A common disease of older cats in which an overactive thyroid speeds up the body, causing weight loss despite a big appetite.

Hypertrophic cardiomyopathy: The most common feline heart disease, in which the wall of the main pumping chamber thickens and the heart works less well.

I

Inflammatory bowel disease: A group of long-lasting digestive conditions in which immune cells inflame the intestinal wall, causing vomiting, diarrhea and weight loss.

IUCN Red List: The international inventory of how close species are to extinction, which sorts them into categories from Least Concern to Extinct.

J

Junior cat: The life stage from about seven months to two years, when a cat reaches adult size and sexual maturity and its energy peaks.

K

Kitten: A cat in its first months of life, from birth until about six months to a year old, a time of rapid growth, learning and vaccinations.

Kitten food: A food with more energy, protein, fat and minerals than adult food, made to support a kitten's fast growth.

Kitten season: The warm months, from spring to autumn, when many unspayed cats give birth and shelters take in far more kittens than usual.

Kneading: The rhythmic pushing of a cat's front paws against a soft surface, a habit that starts in nursing kittens and usually signals comfort.

L

Landrace: A local population of cats that developed over centuries in one region with little planned breeding, before any registry wrote a standard for it.

Lily toxicity: Poisoning by true lilies and daylilies, which can cause fatal kidney failure in cats from even a small amount of leaf, flower or pollen.

Limited-ingredient diet: A food built around few ingredients, often a single protein, used in a vet-guided trial to find out whether a cat has a food allergy.

Litter box: A shallow tray of absorbent material where an indoor cat urinates and defecates, kept in a quiet spot and cleaned daily.

Litter box aversion: When a cat that used to use its litter box begins urinating or defecating elsewhere, often because of pain, stress or a dislike of the box.

Litter scoop: A slotted shovel that lifts clumps and droppings out of a litter box while letting clean litter fall back through.

Lymphoma: A cancer of the lymphocytes, a kind of white blood cell, and the most common cancer in cats.

M

Mammary cancer: Cancer of a female cat's milk glands, usually malignant, and far less likely in cats spayed when young.

Mature cat: A cat of about seven to ten years old, equivalent to a person in their mid-forties to fifties, when screening for age-related disease begins.

Meal feeding: Feeding a cat measured portions at set times each day instead of leaving food out, which helps control weight and spot appetite changes.

Megacolon: A condition in which the colon becomes widened and weak, so hard stool builds up and the cat can no longer pass it normally.

Melanism: An inherited excess of dark pigment that turns an animal's coat black or very dark, as in black leopards, black jaguars and many house cats.

Microchip: A rice-grain-sized implant under a cat's skin that carries a number a scanner can read, linking the cat to its owner's details in a registry.

Microchip cat flap: A cat door that reads the ID microchip under a cat's skin and unlocks only for cats it has been taught to recognise.

Moggy: A British word for an ordinary non-pedigree cat of mixed ancestry, usually short-haired and often a tabby.

Multi-cat household: A home with two or more cats, where enough litter boxes, food stations, perches and hiding spots prevent stress and conflict.

N

Neonatal kitten: A kitten in its first two weeks, born with closed eyes and ears and unable to regulate its own temperature or toilet without its mother.

Neuter: The surgery that removes a male cat's testicles so he cannot father kittens, with fewer urges to roam, fight and spray.

Night howling: Loud calling, wailing or yowling at night, common in older cats and in cats in heat, and sometimes a sign of illness.

No-kill shelter: An animal shelter that saves at least about nine in ten of the animals it takes in, a benchmark often called the 90 percent live release rate.

O

Obesity: Excess body fat that harms a cat's health, raising the risk of diabetes, arthritis and urinary disease.

Obligate carnivore: An animal that must eat animal tissue to get nutrients its body cannot make for itself, as domestic cats must.

Osteoarthritis: Wear and inflammation of the joints that is very common in older cats and often shows up as subtle changes in behavior.

Overgrooming: Licking, chewing or pulling at fur so much that it causes thin or bald patches, with causes ranging from skin disease to stress.

P

Pancreatitis: Inflammation of the pancreas, a hard-to-spot illness in cats that often causes only tiredness and loss of appetite.

Paw pads: The thick, cushioned, hairless pads on the underside of a cat's feet that absorb shock, give grip and help it walk quietly.

Pedigree: A cat whose parents, grandparents and earlier ancestors are recorded by a registry, showing it belongs to a recognised breed.

Periodontal disease: Infection and inflammation of the gums and tissues that hold the teeth, the most common dental problem in cats.

Pet quality: A breeder's label for a pedigree kitten sold as a companion, not for showing or breeding, usually with a neutering agreement.

Pheromone diffuser: A plug-in device that releases a synthetic copy of a cat's facial pheromone, sold to help reduce stress-related behaviours.

Pheromones: Chemical signals that cats release from glands and in urine to communicate with other cats, sensed through the nose and a special organ.

Pica: The habit of chewing or eating things that are not food, such as wool, fabric, plastic or string, which can cause blockages.

Piloerection: The upright bristling of a cat's fur, most often a sign of fear or arousal, which makes the cat look larger.

Play aggression: Biting and clawing during play that is aimed at people's hands and feet, common in young cats that lack playmates.

Poaching: The illegal killing or capture of wild animals, often for their skins, bones, teeth or meat, a major threat to tigers, leopards and other wild cats.

Polycystic kidney disease: An inherited condition in which fluid-filled cysts grow in the kidneys, best known in Persians and related breeds.

Polydactyl: A cat born with extra toes on one or more paws, caused by a common dominant inherited trait that is usually harmless.

Predatory sequence: The chain of behaviours cats use to hunt: watch, stalk, chase, pounce, kill-bite and eat, which good play should echo.

Prescription diet: A food made to help manage a medical condition such as kidney disease or urinary crystals, fed only on a vet's advice.

Prey gift: When a cat brings home dead or live prey, a habit with several possible explanations that is not a sign of ill will.

Purring: The continuous low rumbling sound many cats make when relaxed, and sometimes when hurt or frightened.

Puzzle feeder: A toy or tray that makes a cat work to get its food, adding exercise and mental effort to mealtimes.

Pyometra: A life-threatening infection of the uterus that affects unspayed female cats, usually within weeks after a heat.

Q

Quality of life: A way of judging whether a sick or elderly cat is still comfortable and enjoying life, used to guide end-of-life decisions.

R

Rabies: A viral disease of the nervous system, spread by bites from infected animals, that is almost always fatal once signs appear.

Rabies vaccine: The injection that protects a cat from rabies, required by law for cats in many places and recommended for all.

Raw diet: A diet of uncooked meat, organs and bones, whether home-made or bought, which carries infection and nutrition risks that vets warn about.

Redirected aggression: A sudden attack on a nearby person or pet by a cat that is highly aroused by something it cannot reach.

Reintroduction: Releasing animals into part of their former range where the species has died out, to re-establish a wild population.

Rescue group: A volunteer-run organisation that takes in cats from shelters, streets and owners, cares for them in foster homes and finds them permanent homes.

Resting energy requirement: The calories a resting cat uses each day, a baseline vets multiply by a factor to work out how much food an individual cat needs.

Retractable claws: Cat claws that rest sheathed inside the toe tips and extend only for climbing, gripping and hunting, which keeps them sharp.

Return to field: A shelter practice of neutering, vaccinating and ear-tipping a healthy free-roaming cat, then returning it to where it was found.

Return to owner: The reuniting of a lost cat with its owner, ideally before it enters a shelter, using a microchip, tag or other identification.

Rewilding: Restoring natural processes and, often, missing species such as large predators, to a landscape so that it can run with little human management.

Rex coat: A curly or wavy coat caused by an inherited mutation, seen in breeds such as the Cornish Rex, Devon Rex, Selkirk Rex and LaPerm.

Righting reflex: The reflex that lets a falling cat twist its body in mid-air so it lands on its feet.

Ringworm: A contagious fungal infection of skin, hair and claws that causes patchy hair loss and can spread to people and other pets.

Roundworm: A common intestinal parasite, especially in kittens, that looks like pale spaghetti and can pass to people.

Ruff: A collar of longer fur around a cat's neck and chest, most obvious in breeds such as the Maine Coon and Norwegian Forest Cat.

S

Scent marking: How a cat leaves chemical messages on objects, people and places using glands in its face, paws and body, and in its urine.

Scratching: The natural habit of raking claws against a surface to shed claw sheaths, stretch, mark territory and relax.

Scratching post: A sturdy upright or flat surface covered in rough material that gives a cat a proper place to scratch, stretch and sharpen its claws.

Scruff: The loose skin at the back of a cat's neck, which a mother cat grips to carry kittens but which adult cats should not be lifted or held by.

Seizures: Sudden bursts of abnormal electrical activity in the brain that can cause collapse, twitching, drooling and loss of awareness.

Senior cat: A cat from about 10 or 11 years old, when joint, kidney, thyroid and dental disease become more common and check-ups should be more frequent.

Senior diet: Food marketed for older cats, which varies widely, so the right choice depends on the individual cat's weight, teeth and health.

Separation anxiety: Distress shown by a cat when left alone, such as crying, destroying things, soiling or overgrooming while the owner is away.

Silvervine: A climbing plant from East Asia whose chewed wood and leaves excite most cats, including many that ignore catnip.

Slow blink: A relaxed half-closed blink that cats use to signal comfort and goodwill, and that people can return.

Socialisation period: The early weeks of a kitten's life, roughly two to seven weeks, when gentle handling and new experiences shape how friendly and confident it becomes.

Spay: The surgery that removes a female cat's ovaries, and usually the uterus, so she can no longer become pregnant or go into heat.

Special-needs cat: A cat that needs extra care because of a disability, chronic illness, injury or age, and is often harder to place for adoption.

Spraying: When a cat stands, backs up to a vertical surface and squirts small amounts of urine to leave a scent message.

Squamous cell carcinoma: A cancer of the flat surface cells that appears on the skin of white-eared cats or in the mouth, as a sore that does not heal.

Stomatitis: A painful, long-lasting inflammation of a cat's gums and mouth lining, thought to be an over-reaction of the immune system.

Stray cat: A socialised cat that is lost or has been abandoned and is living outdoors, comfortable with people unlike a true feral cat.

T

Tabby: A coat pattern of stripes, swirls or spots with a dark M-shaped mark on the forehead, found in many breeds and in mixed-breed cats.

Tail language: What the position and movement of a cat's tail reveal about its mood, from a friendly upright tail to a lashing one.

Tapetum lucidum: A mirror-like layer behind a cat's retina that bounces light back through the eye, improving night vision and causing glowing eyes in photos.

Tapeworm: A flat intestinal parasite that cats usually catch by swallowing an infected flea or eating prey, seen as rice-like segments near the tail.

Taurine: An amino acid cats cannot make in enough quantity and must get from food, essential for heart muscle, eyesight and reproduction.

Third eyelid: A thin fold of tissue at the inner corner of a cat's eye that sweeps across the surface to protect and moisten it.

TICA: The International Cat Association, a worldwide registry founded in 1979 that registers pedigree and household pet cats and recognises many newer breeds.

Ticked coat: A coat in which each hair has several bands of colour, giving a soft, shimmering look with few or no stripes on the body.

Tongue papillae: The tiny backward-facing hooks on a cat's tongue that work like a comb for grooming and a rasp for stripping meat from bone.

Tooth resorption: A common, painful dental disease in which the body gradually dissolves part of a cat's tooth, often hidden below the gum line.

Tortoiseshell: A coat of mixed black and orange, or their diluted forms, in patches or brindled swirls, almost always seen in female cats.

Toxoplasmosis: An infection by a microscopic parasite that cats shed in their stool for a short time, and that matters most to pregnant people and those with weak immunity.

Trap-neuter-return: A programme in which free-roaming cats are humanely trapped, neutered, vaccinated, ear-tipped and then returned to where they were found.

Trilling: A short, rolling, rising sound cats use as a friendly greeting, copied from the way a mother calls her kittens.

Trophy hunting: Hunting wild animals for sport and for a trophy such as a head or skin, a debated practice that is legal and regulated in some countries.

Tuxedo cat: A black cat with a white chest, belly and paws, so named for resembling a formal suit, found in many breeds and in mixed-breed cats.

U

Undercoat: The soft, fine, dense layer of fur closest to a cat's skin that provides most of its insulation.

Upper respiratory infection: A contagious infection of the nose, throat and eyes that causes sneezing, discharge and a poor appetite, common in kittens and shelter cats.

Urinalysis: A set of tests on a cat's urine that reveals kidney function, infection, crystals, diabetes and more.

Urinary blockage: A life-threatening emergency in which the urethra is plugged so a cat cannot pass urine, most often in male cats.

V

Vaccine titer: A blood test that measures antibodies to a germ, sometimes used to judge whether a cat is protected after vaccination.

Van pattern: A coat that is almost entirely white, with colour limited to the head and tail and sometimes a few small spots on the body.

Vestibular disease: A disturbance of the balance system that causes a head tilt, stumbling, rolling and flicking eye movements.

Vomeronasal organ: A small scent-analysing organ in the roof of a cat's mouth that reads chemical signals such as pheromones.

W

Weaning: The gradual switch from mother's milk to solid food, which usually starts at about four weeks and is mostly complete by eight to ten weeks.

Wellness exam: A routine vet visit for a healthy-looking cat to check its body, update vaccines and parasite control, and catch problems early.

Wet food: Cat food sold in cans, pouches or trays, containing roughly 70 to 80 percent water, which helps a cat get more fluid.

Whiskers: The long, stiff, touch-sensitive hairs on a cat's muzzle, brows, chin and forelegs that help it sense nearby objects and air movement.

Wildlife corridor: A strip of habitat or a crossing structure that links separate wild areas so animals can travel between them safely.

Window perch: A shelf, hammock or bed that attaches to a window so an indoor cat can sit and watch the outside world.

Z

Zoomies: Short, sudden bursts of high-speed running and leaping, common in young cats, usually in the evening or early morning.