Every field has its jargon, and pet health and veterinary care is worse than most. This glossary covers the 55 terms that come up again and again in our guides and in the questions readers send us. Definitions are short on purpose: enough to unblock you, with links to deeper guides throughout the site when you want the full story.

Abscess

A pocket of pus that forms when bacteria infect an area of the body. Abscesses are painful and require veterinary treatment to drain and heal properly.

Allergen

A substance that triggers an allergic reaction in your pet. Common allergens include certain foods, pollen, dust, and insect bites.

Anesthesia

A medication that puts your pet to sleep or numbs an area so they don’t feel pain during surgery or procedures. Your vet will monitor your pet closely while under anesthesia.

Antibiotic

A medicine that kills bacteria or stops bacterial infections from spreading. Antibiotics are prescribed for infections like ear infections and wounds.

Arthritis

A condition where joints become inflamed and stiff, usually due to age or wear and tear. Pets with arthritis may have trouble moving or climbing stairs.

Benign

A medical term meaning a growth or condition is not cancerous and not dangerous. Benign tumors typically grow slowly and don’t spread to other parts of the body.

Biopsy

A procedure where a small tissue sample is taken and examined under a microscope to diagnose disease. Biopsies help vets determine if a growth is cancerous.

Bloodwork

A blood test that measures different components like red and white blood cells, proteins, and organ function. Bloodwork helps vets diagnose infections, organ problems, and other health issues.

Breed-specific Health Issues

Health problems that occur more frequently in certain dog or cat breeds due to their genetics. For example, hip dysplasia is common in large dog breeds.

Cardiac

Relating to the heart. Cardiac disease means there’s a problem with how the heart pumps blood throughout the body.

Chronic

A long-lasting or recurring health condition that develops slowly over time. Chronic conditions like diabetes or kidney disease require ongoing management.

Cognitive Dysfunction

A condition in older pets where their brain function declines, similar to dementia in humans. Symptoms include confusion, disorientation, and changes in sleep patterns.

Dental Prophylaxis

A professional cleaning of your pet’s teeth performed by a veterinarian under anesthesia. Regular dental prophylaxis helps prevent tartar buildup and tooth disease.

Dewormer

A medication that kills parasitic worms living in your pet’s intestines. Puppies and kittens typically need to be dewormed multiple times.

Diagnosis

The identification of what disease or condition your pet has based on symptoms, tests, and examination. An accurate diagnosis helps your vet create the right treatment plan.

Diarrhea

Loose or watery stool that occurs when your pet’s digestive system is upset. Diarrhea can be caused by diet changes, infections, or stress.

Dysplasia

An abnormal development of joints or tissues, often present from birth. Hip and elbow dysplasia are common in large dog breeds and can cause pain and arthritis.

Euthanasia

The humane end of life for a suffering pet to relieve pain and distress. This decision is made with a veterinarian when a pet has a terminal illness or severe quality of life issues.

Fecal Exam

A microscopic examination of your pet’s stool to check for parasites and other intestinal issues. Vets recommend regular fecal exams as part of routine wellness care.

Fungal Infection

An infection caused by fungi that can affect the skin, nails, or internal organs. Ringworm is a common fungal skin infection in pets.

Generic Medication

A medication with the same active ingredient as a brand-name drug but usually costs less. Generic medications are safe and effective alternatives to brand-name versions.

Heartworm

A parasitic worm transmitted by mosquitoes that lives in the heart and lungs of pets. Heartworm is serious and can be fatal if left untreated, but is preventable with medication.

Hip Dysplasia

A genetic condition where the hip joint doesn’t develop properly, causing looseness and arthritis. Dogs with hip dysplasia may limp, have difficulty rising, or show pain when exercising.

Histamine

A chemical released during allergic reactions that causes itching, swelling, and inflammation. Antihistamine medications help control allergic symptoms in pets.

Immune System

Your pet’s body’s defense system that fights off infections and disease. A weakened immune system makes pets more vulnerable to illness.

Incision

A surgical cut made by a veterinarian during an operation or procedure. Incisions need to be kept clean and dry while they heal.

Inflammation

Swelling, redness, and warmth in a part of the body caused by infection or injury. Inflammation is your pet’s body trying to protect itself and heal.

Intramuscular Injection

A shot given directly into muscle tissue, typically in the thigh or shoulder. Intramuscular injections are often used for vaccines and certain medications.

Jaundice

A yellowing of the skin, gums, and whites of the eyes caused by liver problems. Jaundice indicates that the liver is not functioning properly and needs immediate veterinary attention.

Kennel Cough

A contagious respiratory infection in dogs that causes a dry, hacking cough. Kennel cough spreads easily in places where many dogs gather and usually goes away on its own.

Lesion

An area of skin or tissue that looks different from surrounding healthy areas due to disease or injury. Lesions might appear as bumps, sores, or discolored patches.

Lipoma

A benign fatty tumor that grows under the skin and is common in older dogs. Lipomas are usually harmless but should be monitored by a vet.

Malignant

A medical term meaning a growth or condition is cancerous and dangerous. Malignant tumors grow quickly and can spread to other parts of the body.

Microchip

A tiny electronic chip implanted under your pet’s skin that contains identification information. A microchip helps reunite lost pets with their owners if they’re found by a shelter or vet.

Neutered

A surgical procedure that removes a male pet’s testicles to prevent reproduction. Neutering has health and behavioral benefits for male dogs and cats.

Obesity

A condition where a pet weighs significantly more than is healthy for their size and breed. Obesity in pets increases the risk of diabetes, joint problems, and heart disease.

Otitis

Inflammation or infection of the ear, often caused by bacteria, yeast, or allergies. Otitis causes discomfort and requires veterinary treatment to prevent complications.

Parasite

An organism that lives on or inside your pet’s body and feeds on them, causing harm. Common parasites include fleas, ticks, worms, and mites.

Prognosis

The expected outcome of a disease or condition based on medical knowledge and your pet’s individual situation. A good prognosis means your pet is likely to recover well.

Prophylactic

A treatment or medication given to prevent disease rather than treat it. Preventative flea and tick medication is a common prophylactic treatment.

Pus

A thick, yellowish fluid made up of white blood cells, bacteria, and dead tissue. Pus indicates an active infection that needs treatment.

Radiograph

An X-ray image that allows vets to see inside your pet’s body to diagnose problems. Radiographs help detect broken bones, organ issues, and other internal problems.

Seizure

A sudden, uncontrolled burst of electrical activity in the brain that causes convulsions or loss of consciousness. Seizures can be caused by epilepsy, toxins, or other medical conditions.

Spayed

A surgical procedure that removes a female pet’s uterus and ovaries to prevent reproduction. Spaying has health and behavioral benefits for female dogs and cats.

Subcutaneous Injection

A shot given under the skin, often between the shoulder blades. Subcutaneous injections are commonly used for vaccines and certain medications.

Suture

A surgical stitch used to close wounds or incisions after surgery. Sutures typically need to be removed after 10 to 14 days.

Symptom

A sign or change in your pet’s body or behavior that indicates illness or health problems. Vomiting, lethargy, and loss of appetite are common symptoms.

Therapy

A treatment plan used to manage or cure a health condition in your pet. Therapy might include medication, surgery, physical rehabilitation, or dietary changes.

Titer Test

A blood test that measures whether your pet has immunity to certain diseases like rabies. Titer tests can sometimes be used instead of booster vaccines.

Toxic

Poisonous or harmful to your pet’s health. Many common household items and foods are toxic to dogs and cats.

Tumor

An abnormal growth of cells in the body that can be either benign or cancerous. Tumors should be evaluated by a vet to determine if they’re dangerous.

Ultrasound

A medical imaging technique that uses sound waves to create a picture of your pet’s internal organs. Ultrasounds are useful for examining the heart, liver, kidneys, and reproductive organs.

Vaccination

An injection of a weakened or inactive form of a disease that helps your pet’s immune system recognize and fight that disease. Vaccinations protect pets from serious and potentially fatal illnesses.

Wellness Exam

A routine veterinary checkup to evaluate your pet’s overall health and catch problems early. Wellness exams typically include physical examination, bloodwork, and discussion of diet and exercise.

Zoonotic

A disease that can spread from animals to humans. Rabies and ringworm are examples of zoonotic diseases that pets can transmit to people.