Weaning (wee-nuhng): Transitioning from the queen’s milk or milk replacement formula to solid food, which is often a stressful process for kittens and may result in diarrhea due to the introduction of new proteins and other nutrients

Western blot: A test that is considered confirmatory for the presence of Feline Immunodeficiency Virus (FIV) antibodies in a cat’s blood

Wheezing (wee-zuhng): An abnormal sound caused by airway narrowing due to constriction, partial blockage, inflammation or other health issues, which may occur with hairballs, asthma, and polyps in the sinus or throat

Whisker fatigue: The stimulatory overload to the brain caused by whiskers brushing against food and water dishes can make cats feel stressed or agitated and can be remedied by providing shallow dishes with low sides

Wobbly Kitten Syndrome: A neurologic condition, known as cerebellar hypoplasia or CH, affecting kittens and cats that is most often caused when a pregnant cat is exposed to feline parvovirus, the virus that causes feline panleukopenia, whether from a natural infection or from a vaccination


X chromosome (kroh-muh-sohm): A cat with two X chromosomes is female and a cat with an X and a Y chromosome is male. Calico is a distinctive coat color pattern linked to the X chromosome, and over 95% of calico cats are female.

Xiphisternum (zif-uh-stur-nuhm): The cartilaginous process (extension) forming the lowermost part of the sternum (breastbone)

Xiphoid process (zai-foyd): Another term for the xiphisternum, which may stick out on the chest, especially in kittens and young cats whose bones are still developing

X-rays: Medical x-rays (radiographs) use high-energy electromagnetic radiation to generate images of tissues and structures inside the body and can provide useful diagnostic information

Xylazine (zai-luh-zeen): A central nervous system suppressant used in veterinary medicine as a sedative, anesthetic, muscle relaxant and emetic

Xylocaine (zai-luh-kayn): An injectable anesthetic used as a treatment for abnormal heart rhythms or cardiac arrhythmia and also to numb the skin and mucous membranes