Veterinary is the describing word for anything to do with medical care for animals: veterinary medicine, a veterinary clinic, veterinary school, veterinary care, veterinary bills, a veterinary nurse. It sits in front of a noun almost every time — you would not normally say 'the treatment was veterinary'. Notice the difference from veterinarian: veterinarian is the person, veterinary is the field, the study, the kind of care. 'She is a veterinarian' but 'she studies veterinary medicine'. The word carries a formal, official flavour. It belongs on signs, on university course lists, in laws and regulations, and in writing; in ordinary talk people say 'the vet's' — 'the vet's bill', 'the vet's office' — rather than 'the veterinary bill'. In British English, veterinary is the usual full form, and 'veterinary surgeon' is the formal title for what Americans call a veterinarian. In Britain it can also stand alone as a noun meaning a vet, but that use is old-fashioned and rare now; treat it as a describing word. Pronunciation is where it hurts. It is long, and even native speakers squeeze it — Americans commonly say something like VET-er-in-air-ee, while British speakers often crush it down to VET-rin-ree or even VET-ner-ee. All of these are normal; do not think you must hit every syllable perfectly.